KR101127787B1 - Liquid crystal display - Google Patents

Abstract

An optical compensation film comprising a first polarizing film, a first retardation region in contact with the first polarization film, and a second retardation region in contact with the first retardation region, a first substrate, a liquid crystal layer made of a liquid crystal material, and 2. A liquid crystal display in which two substrates are arranged in this order and liquid crystal molecules of the liquid crystal material are aligned in parallel with respect to the surface of the pair of substrates at the time of black display, wherein in-plane refractive indices nx and ny (nx? Ny), Using the refractive index nz in the thickness direction and the thickness d of the film, the in-plane retardation Re of the first retardation region defined by Re = (nx-ny) × d is 20 nm or less, and Rth = ((nx + ny) / 2-nz) xd, and the retardation Rth of the thickness direction of a 1st phase difference area | region is 20 nm-120 nm, and is comprised from the composition containing the discotic liquid crystal compound in which the 2nd phase difference area was substantially vertically oriented, , The second phase difference zero The reverse slow axis is a liquid crystal display device parallel to the transmission axis of the first polarizing film and the slow axis direction of the liquid crystal molecules at the time of black display.

Description

Liquid crystal display {LIQUID CRYSTAL DISPLAY}

1 is a schematic diagram showing an example of a pixel region of a liquid crystal display of the present invention.

2 is a schematic view showing an example of the liquid crystal display of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to an in-plane switching mode liquid crystal display device which displays by applying an electric field in a horizontal direction to liquid crystal molecules oriented in a horizontal direction.

As a liquid crystal display device, the method of sandwiching the liquid crystal layer which twisted nematic liquid crystal between two orthogonal polarizing plates, and applying an electric field to a perpendicular direction with respect to a board | substrate, so-called TN mode, is widely used. In this system, since the liquid crystal rises with respect to the substrate at the time of black display, birefringence by the liquid crystal molecules occurs and the light leakage occurs when viewed obliquely. In response to this problem, a method of optically compensating a liquid crystal cell to prevent this light leakage by using a film in which the liquid crystal molecules are hybrid oriented has been put into practical use. However, even when the liquid crystal molecules are used, it is very difficult to completely optically compensate the liquid crystal cell without problems, and there is a problem in that the gray level inversion in the downward direction of the screen cannot be suppressed.

In order to solve this problem, a liquid crystal display device using a so-called inplane switching (IPS) mode in which a transverse electric field is applied to a liquid crystal, or projections or slit electrodes formed in a panel by vertically aligning liquid crystals having negative dielectric anisotropy Orientation divided vertical alignment (VA) mode has been proposed and put into practical use. In recent years, these panels are not only used for monitors, but are being developed as TVs, and thus the brightness of the screens is greatly improved. For this reason, some light leakage in the diagonal diagonal incidence direction at the time of black display which did not become a problem in these operation modes conventionally has been brought to the present as a cause of the fall of display quality.

As one of the means of improving the viewing angle of this color tone or black display, disposing an optical compensation material having birefringence property between the liquid crystal layer and the polarizing plate is also examined in the IPS mode. For example, when a birefringent medium orthogonal to each other is arranged between the substrate and the polarizing plate having an optical axis having a function of compensating the increase and decrease of the retardation of the liquid crystal layer at the time of tilting, the white display or halftone display is viewed in an oblique direction. It is disclosed that the coloring can be improved (see Japanese Patent Laid-Open No. 9-80424). Moreover, the method using the optical compensation film which consists of a styrene polymer or discotic liquid crystalline compound which has negative birefringence (Japanese Unexamined Patent Publication No. 10-54982, Japanese Unexamined Patent Publication No. 11-202323, and Japanese Unexamined Patent Publication) 9-292522) or a method of combining a film having birefringence positive and having an optical axis in-plane of the film as an optical compensation film and a film having birefringence positive and having an optical axis in the normal direction of the film (Japanese Laid-Open Patent Publication). Japanese Patent Application Laid-Open No. 11-133408), a method of using a biaxial optical compensation sheet having a retardation of 1/2 wavelength (see Japanese Laid-Open Patent Publication No. Hei 11-305217), and using a film having a negative retardation as a protective film for a polarizing plate. And a method of forming an optical compensation layer having a positive retardation on this surface (see JP-A-10-307291) have been proposed.

However, since most of the proposed methods are methods for eliminating the birefringence anisotropy of the liquid crystal in the liquid crystal cell and improving the viewing angle, light leakage based on the deviation from orthogonality of the polarization axis crossing angles when the orthogonal polarizer is viewed obliquely is sufficient. There is a problem that can not be solved. In addition, even in the manner in which the light leakage can be compensated, it is very difficult to completely optically compensate the liquid crystal cell without problems. Moreover, in the optical compensation sheet for IPS mode liquid crystal cells which perform optical compensation in a stretched birefringent polymer film, it is necessary to use a some film, As a result, the thickness of an optical compensation sheet becomes thick and it is disadvantageous for thinning a display apparatus. Moreover, since an adhesion layer is used for lamination of a stretched film, the adhesion layer shrinks by the change of temperature-humidity, and defects, such as peeling and curvature between films, may arise.

This invention is made | formed in view of all the said troubles, Comprising: It aims at providing the IPS type | mold liquid crystal display device by which not only the display quality but also the viewing angle was remarkably improved with simple structure.

The objective of this invention was achieved by the liquid crystal display device of following (1)-(10).

(1) An optical compensation film comprising a first polarizing film, a first retardation region in contact with the first polarization film, and a second retardation region in contact with the first retardation region, a first substrate, and a liquid crystal layer made of a liquid crystal material And a second substrate and a second polarizing film are arranged in this order, and the liquid crystal molecules of the liquid crystal material are aligned in parallel with respect to the surfaces of the pair of substrates at the time of black display.

Using the in-plane refractive indices nx and ny (nx ≥ny), the refractive index nz in the thickness direction, and the film thickness d

Re = (nx-ny) × d

In-plane retardation Re of the 1st phase difference region defined by is 20 nm or less, and

Rth = ((nx + ny) / 2-nz) × d

The retardation Rth in the thickness direction of the first retardation region defined by is 20 nm to 120 nm, and is composed of a composition containing a discotic liquid crystal compound in which the second retardation region is substantially vertically aligned, A liquid crystal display device wherein the slow axis is parallel to the transmission axis of the first polarizing film and the slow axis direction of the liquid crystal molecules at the time of black display.

(2) The liquid crystal display device of (1), wherein Re of the second retardation region of the optical compensation film is 50 nm to 200 nm.

(3) The first retardation region is composed of a plurality of layers, the layer in contact with the second retardation region among the plurality of layers is an alignment film, and the second retardation region is at least a disco at the discotic liquid crystal compound and the air interface side. The liquid crystal display device of (1) or (2) containing the air interface aligning agent which reduces the inclination angle of the director of a tick liquid crystalline compound.

(4) The liquid crystal display device according to any one of (1) to (3), having a second polarizing film on the outside of the second substrate.

On the other hand, the "outer side of a 2nd board | substrate" means the side in which the said liquid crystal layer is not located when it sees centering on the said 2nd board | substrate.

(5) Liquid crystal display device of (4) which has a pair of protective film arrange | positioned through the said 2nd polarizing film, and phase difference Rth of the thickness direction of the protective film of the side close to a liquid crystal layer among the said pair of protective films is 40 nm or less. .

(6) (4) or (5) which has a pair of protective film arrange | positioned through the said 2nd polarizing film, and phase difference Rth of the thickness direction of the protective film of the side close to a liquid crystal layer among the said pair of protective films is 20 nm or less. Liquid crystal display device.

(7) Any of (4)-(6) which has a pair of protective film arrange | positioned through the said 2nd polarizing film, and the thickness of the protective film of the side close to a liquid crystal layer among the said pair of protective films is 10-60 micrometers. One liquid crystal display.

(8) The liquid crystal display device according to any one of (4) to (7), wherein the protective film near the liquid crystal layer is a cellulose acetate film or a norbornene-based film among the pair of protective films arranged with the second polarizing film interposed therebetween. .

(9) (4)-(which has a layer containing the rod-shaped liquid crystalline compound vertically oriented with the cellulose acetate film among the pair of protective films arrange | positioned with the said 2nd polarizing film interposed therebetween. 8) Any one of liquid crystal display devices.

(10) The liquid crystal according to any one of (1) to (9), wherein the first retardation region is composed of a plurality of layers, and a layer in contact with the first polarizing film among the plurality of layers functions as a protective film of the first polarizing film. Display device.

In the present invention, the in-plane retardation Re defined by Re = (nx-ny) × d is 20 nm using the refractive indices nx and ny (nx? Ny) in the layer plane, the refractive index nz in the thickness direction, and the thickness d of the film. The Retardation Rth in the thickness direction defined below and further defined by Rth = ((nx + ny) / 2-nz) × d is 50 nm to 50 nm, which is substantially perpendicularly aligned with the first retardation region having 20 nm to 120 nm. In the second retardation region composed of a discotic liquid crystal compound having a thickness of 200 nm, the slow axis of the second retardation region is parallel to the transmission axis of the first polarizing film and the slow axis direction of the liquid crystal molecules at the time of black display, and further to the second phase difference region. By arranging the retardation regions to be on the liquid crystal layer side than the first retardation region, the contrast decreases when the absorption axes of the two polarizing plates deviate from 90 degrees when viewed in the inclined azimuth direction without changing the characteristics in the front direction at all. , Especially 4 The fall of contrast in the inclination direction of 5 degrees can be improved. Moreover, contrast improvement can further be implement | achieved by setting Rth of the protective film of a 2nd polarizing film to 40 nm or less, or thickness to 60 micrometers or less.

Embodiments of the Invention

EMBODIMENT OF THE INVENTION Below, one Embodiment of the liquid crystal display device of this invention and its structural member are demonstrated one by one. In addition, the numerical range shown using "-" in this specification means the range which includes the numerical value described before and after "-" as a lower limit and an upper limit.

In this specification, "parallel" and "orthogonal" mean that it exists in the range less than an exact angle of +/- 10 degrees. It is preferable that this range is less than +/- 5 degree, and, as for the error with an exact angle, it is more preferable that it is less than +/- 2 degree. In addition, "substantially vertical" means that it is in the range less than +/- 20 degrees rather than an exact vertical angle. It is preferable that this range is less than +/- 15 degrees, and, as for the error with an exact angle, it is more preferable that it is less than +/- 10 degrees. In addition, "ground axis" means the direction in which a refractive index becomes largest. In addition, the measurement wavelength of refractive index is a value in (lambda) = 550 nm of visible range unless there is particular description.

In the present specification, the "polarizing plate" is cut to a size embedded in a long polarizing plate and a liquid crystal device, unless specifically limited (in this specification, "foundation" shall also include "punching", "cutting", etc.). ) Is used to include all polarizers. In addition, although a "polarizing film" and a "polarizing plate" are distinguished and used in this specification, a "polarizing plate" shall mean the laminated body which has a transparent protective film which protects the said polarizing film on at least one surface of a "polarizing film."

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail using drawing. 1 is a schematic diagram illustrating an example of a pixel region of a liquid crystal display of the present invention. It is a schematic diagram of one Embodiment of the liquid crystal display device of this invention.                     

[Liquid crystal display device]

The liquid crystal display device shown in FIG. 2 includes a first polarizing film 8, an optical compensation film 10, a first substrate 14, a liquid crystal layer 16, a second substrate 18, and a first product. It has a 2 polarizing film 21. The 1st polarizing film 8 and the 2nd polarizing film 21 are pinched by the protective films 7a and 7b and the protective films 20a and 20b, respectively. The optical compensation film 10 is composed of a first retardation region 11 including a protective film 7b in contact with the first polarizing film 8 and a second retardation region 12 in contact with the first phase region 11. Consists of.

In the liquid crystal display of FIG. 2, the liquid crystal cell consists of the 1st board | substrate 14 and the 2nd board | substrate 17, and the liquid crystal layer 16 clamped by these. The product Δn? D of the thickness d (μm) of the liquid crystal layer and the refractive index anisotropy Δn is in the transmission mode, in the range of 0.2 to 0.4 μm in the IPS type having no torsion structure. In this range, since the white display brightness is high and the black display brightness is small, a bright and high contrast display device is obtained. An alignment film (not shown) is formed on the surface in contact with the liquid crystal layer 16 of the substrates 14 and 18, and the rubbing treatment direction carried out on the alignment film while aligning the liquid crystal molecules almost parallel to the surface of the substrate. (15 and 19) etc., the orientation of the liquid crystal molecules in the voltage-free state or the low applied state is controlled. Moreover, the electrode (not shown in FIG. 2) which can apply voltage to liquid crystal molecule is formed in the inner surface of the board | substrate 14 or 17. FIG.

In FIG. 1, the orientation of the liquid crystal molecule in the one pixel area | region of the liquid crystal layer 16 is shown typically. 1 shows the orientation of liquid crystal molecules in a region of a very small area corresponding to one pixel of the liquid crystal layer 16 in the rubbing direction 4 and the substrate 14 of the alignment film formed on the inner surfaces of the substrates 14 and 18. It is a schematic diagram shown with the electrodes 2 and 3 which can apply voltage to the liquid crystal molecule formed in the inner surface of 18). When active driving is performed using a nematic liquid crystal having positive dielectric anisotropy as a field effect type liquid crystal, the orientation direction of liquid crystal molecules in a voltage-free state or a low applied state is 5a and 5b, and black display is obtained at this time. . When applied between the electrodes 2 and 3, the liquid crystal molecules change their alignment directions in the 6a and 6b directions depending on the voltage. Usually, brightness display is performed in this state.

In FIG. 2, the transmission axis 9 of the first polarizing film 8 and the transmission axis 22 of the second polarizing film 21 are arranged orthogonal to each other. The optical compensation film 10 is comprised by the two area | regions of the 1st phase difference area | region 11 and the 2nd phase difference area | region 12. As shown in FIG. In addition, the slow axis 13 of the second retardation region 12 is the slow axis direction 17 of the liquid crystal molecules in the transmission axis 9 of the first polarizing film 8 and the liquid crystal layer 16 at the time of black display. Parallel to the second retardation region 12 is disposed closer to the liquid crystal layer 16 than the first retardation region 11. Optical characteristics of the two regions constituting the optical compensation film will be described later.

In the liquid crystal display shown in FIG. 2, although the 1st polarizing film 8 showed the structure pinched by two protective films 7a and 7b, the protective film 7b may not be provided. In the case where the protective film 7b is disposed, in the present invention, the protective film 7b becomes one of the layers constituting the first phase difference region 11. In the liquid crystal display device shown in FIG. 2, the second polarizing film 21 is also sandwiched by two protective films 20a and 20b. It is preferable that the phase difference Rth of the thickness direction of the protective film 20a of the side near the liquid crystal layer 16 is 40 nm or less (more preferably 20 micrometers or less), or 60 micrometers or less in thickness.

In addition, although the aspect of the display apparatus of the transmissive mode provided with the upper polarizing plate and the lower polarizing plate was shown in FIG. 2, this invention may be the sun of the reflection mode provided with only one polarizing plate, In this case, the optical path in a liquid crystal cell Since is doubled, the value of the optimum Δn? D becomes about 1/2 of the above.

The liquid crystal display device of this invention is not limited to the structure shown in FIG. 1, FIG. 2, and may contain the other member. For example, you may arrange a color filter between a liquid crystal layer and a polarizing film. In addition, antireflection treatment or hard coat may be performed on the surface of the protective film of the polarizing film. Moreover, you may use what gave electroconductivity to a structural member. Moreover, when using as a transmission type, the backlight which uses a cold cathode or a hot cathode fluorescent tube, or a light emitting diode, a field emission element, an electroluminescent element as a light source can be arrange | positioned at the back surface. In addition, a reflective polarizing plate, a diffusion plate, a prism sheet, or a light guide plate may be disposed between the liquid crystal layer and the backlight. In addition, the liquid crystal display device of the present invention may be a reflective type. In this case, only one polarizing plate is disposed on the observation side, and the reflective film is disposed on the rear surface of the liquid crystal cell or the lower substrate of the liquid crystal cell. Of course, it is also possible to form the front light using the light source on the liquid crystal cell observation side.

The liquid crystal display device of the present invention includes an image direct view type, an image projection type, and a light modulation type. As for this invention, the aspect applied to the active-matrix liquid crystal display device which used the 3-terminal or 2-terminal semiconductor element, such as TFT and MIM, is especially effective. Of course, the aspect applied to the passive matrix liquid crystal display device called time division drive is also effective.

Hereinafter, the preferable optical characteristic of the various member which can be used for the liquid crystal display device of this invention, the material used for a member, its manufacturing method, etc. are demonstrated in detail.

[First Retardation Region of Optical Compensation Film]

The optical properties of the first retardation region are in-plane retardation defined by Re = (nx-ny) x d using in-plane refractive indices nx and ny (nx ≥ ny), refractive index nz in the thickness direction, and thickness d of the film. It is more preferable that Re is 20 nm or less, 10 nm or less, and it is most preferable that it is 5 nm or less. Moreover, it is more preferable that the retardation Rth of the thickness direction defined by Rth = ((nx + ny) / 2-nz) xd is 20 nm-120 nm, and it is the range of 40 nm-100 nm. On the other hand, when the protective film 7b which protects the 1st polarizing film 8 has optical anisotropy, since the protective film 7b is a layer which comprises the 1st phase difference area | region 11, it is a layer different from Rth of this protective film. It is necessary for the sum total of Rth of to be 40 nm-100 nm.

Examples of the retardation film having optical properties include a retardation film made of a birefringent polymer film and a retardation film having an optically anisotropic layer formed by applying or transferring a low molecular or polymer liquid crystalline compound on a transparent support. Can be.

The phase difference film which consists of a birefringent polymer film which has the said optical characteristic can be easily formed even if it biaxially stretches a polymer film. Moreover, the cellulose acylate which expresses this optical characteristic only by being flexible, without extending | stretching, can be used preferably. As such cellulose acylate, what is described in Unexamined-Japanese-Patent No. 2002-90541 can be used. As the material of the polymer film, a synthetic polymer (eg, polycarbonate, polysulfone, polyethersulfone, polyacrylate, polymethacrylate, norbornene resin, cellulose acetate) is generally used.

A retardation film formed on a transparent support by coating or transfer, wherein a rod-shaped cholesteric liquid crystal composition containing a chiral structural unit is immobilized after aligning its helical axis almost perpendicular to the substrate, or having a negative birefringence. The horizontal alignment (director is perpendicular | vertical to a board | substrate), and the thing which fixed-fixed the polyimide polymer on the board | substrate can be illustrated.

[Second phase difference region of the optical compensation film]

The second retardation region includes a discotic liquid crystal compound that is substantially vertically aligned, and its slow axis is disposed in parallel with the transmission axis of the first polarizing film and the slow axis direction of the liquid crystal molecules at the time of black display. It is preferable that it is 50 nm-200 nm, and, as for Re of a 2nd phase difference area | region, 80 nm-160 nm are more preferable. The adjustment of Re is performed by controlling the thickness of the discotic liquid crystal layer to be formed by coating. In addition, it is necessary for the discotic liquid crystalline compound to orientate substantially perpendicular (average inclination angle of the range of 70-90 degree) with respect to a film surface. If the average inclination angle is smaller than this, the distribution of light leakage becomes asymmetric.

Discotic liquid crystalline compounds can be found in various literatures (C. Destrade et al., Mol. Crysr. Liq. Cryst., Vol. 71, page 111 (1981)); Japanese Chemical Sculpture, Quarterly Chemical Summary, No. 22, Chemistry of Liquid Crystals, Chapter 5, Chapter 10, Section 2 (1994)); B. Kohne et al., Angew. Chem. Soc. Chem. Comm., Page 1794 (1985)); J. Zhang et al., J. Am. Chem. Soc., Vol. 116, page 2655 (1994). Regarding polymerization of the discotic liquid crystalline compound, there is a description in JP-A-8-27284.

It is preferable that a discotic liquid crystalline compound has a polymeric group so that fixation is possible by superposition | polymerization. For example, a structure in which a polymerizable group is bonded to a discotic core of a discotic liquid crystalline compound as a substituent is conceivable. However, if the polymerizable group is directly connected to the discotic core, it becomes difficult to maintain the alignment state in the polymerization reaction. Therefore, a structure having a linking group between the discotic core and the polymerizable group is preferable. That is, it is preferable that the discotic liquid crystalline compound which has a polymeric group is a compound represented by a following formula.

D (-LP) _n

In formula, D is a disk-shaped core, L is a bivalent coupling group, P is a polymeric group, n is an integer of 4-12. Preferable specific examples of the disk-shaped core (D), the divalent linking group (L) and the polymerizable group (P) in the above formula are (D1) to (D15) and (L1) described in JP 2001-4837 A, respectively. As (L25), (P1)-(P18), the content of the said publication can be used preferably.

The second retardation region may consist only of a layer formed of a composition containing a discotic liquid crystal, or may consist of a layer formed of a composition containing a discotic liquid crystal and other layers. In the latter case, a laminate with an optically isotropic film such as a laminate with the stretched polystyrene film or a cycloolefin type can be preferably used.

[Bar type liquid crystalline compound]

The liquid crystal display of the present invention may have a retardation layer formed of a composition containing a rod-like liquid crystal compound. As described later, the protective film of the second polarizing film is preferably made of a retardation layer formed of a polymer film, preferably a composition containing a polymer film of cellulose acylate and a rod-like liquid crystal compound. As said rod-like liquid crystalline compound, azomethines, azoxy compounds, cyano biphenyls, cyano phenyl esters, benzoic acid esters, cyclohexane carboxylic acid phenyl esters, cyano phenyl cyclohexane, and cyano substituted phenyl pyrimes Deans, alkoxy substituted phenylpyrimidines, phenyldioxanes, transs and alkenylcyclohexylbenzonitriles are preferably used. Not only the low molecular liquid crystalline molecules described above, but also high molecular liquid crystalline molecules can be used.

It is preferable that the liquid crystalline compound used in the present invention, for example, a rod-like liquid crystalline compound, is substantially vertically aligned. Substantially vertical means that in the case of a rod-like liquid crystalline compound, the angle between the film surface and the director of the rod-like liquid crystalline compound is within a range of 70 ° to 90 °. Moreover, in the case of a discotic liquid crystalline compound, it means that the average angle (average tilt angle) of the disk surface and the surface of an optically anisotropic layer exists in the range of 70 degrees-90 degrees. These liquid crystalline compounds may be inclined or may be inclined so as to gradually change (hybrid alignment). Even in the case of oblique orientation or hybrid orientation, the average inclination angle is preferably 70 ° to 90 °, more preferably 75 ° to 90 °, and most preferably 80 ° to 90 °.

Retardation Layer Forming Method Containing Liquid Crystalline Compound

The retardation layer containing the liquid crystalline compound is a coating liquid containing a rod-like liquid crystalline compound or a discotic liquid crystalline compound or the following polymerizable initiator, an air interface aligning agent or another additive is applied onto the vertical alignment film formed on the support. By forming.

As a solvent used for preparation of a coating liquid, an organic solvent is used preferably. Examples of organic solvents include amides (eg N, N-dimethylformamide), sulfoxides (eg dimethyl sulfoxide), heterocyclic compounds (eg pyridine), hydrocarbons (eg benzene, hexane), alkyl halides ( Examples include chloroform, dichloromethane), esters (eg methyl acetate, butyl acetate), ketones (eg acetone, methylethyl ketone), ethers (eg tetrahydrofuran, 1,2-dimethoxyethane) . Alkyl halides and ketones are preferred. You may use together 2 or more types of organic solvents. Application | coating of a coating liquid can be performed by a well-known method (for example, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method).

It is preferable to maintain and fix an orientation state for the liquid crystalline compound oriented vertically. It is preferable to perform fixation by the polymerization reaction of the polymeric group (P) introduce | transduced into a liquid crystalline compound. The polymerization reaction includes a thermal polymerization reaction using a thermal polymerization initiator and a photopolymerization reaction using a photopolymerization initiator. Photopolymerization reaction is preferred. Examples of photopolymerization initiators include α-carbonyl compounds (see US Pat. No. 23,67661, US 2367670), acyloinether (see US Pat. No. 2448828), α-hydrocarbon substituted aromatic acyl in compounds (US Pat. 2722512 specification), polynuclear quinone compounds (see US Pat. No. 3046127, pp. 2951758), combinations of triarylimidazole dimers with p-aminophenylketone (as described in US Pat. No. 3549367), acridine And phenazine compounds (Japanese Laid-open Patent Publication No. 60-105667, described in US Patent 4239850 specification) and Oxadiazole compounds (described in US Patent 4212970 specification).

It is preferable that it is 0.01-20 mass% of solid content of a coating liquid, and, as for the usage-amount of a photoinitiator, it is more preferable that it is 0.5-5 mass%. It is preferable to use ultraviolet-ray for the light irradiation for superposition | polymerization of a discotic liquid crystalline molecule. It is preferable that it is 20 mJ / cm <2> -50J / cm <2>, and, as for irradiation energy, it is more preferable that it is 100-800 mJ / cm <2>. In order to accelerate the photopolymerization reaction, light irradiation may be performed under heating conditions. It is preferable that the thickness of a phase difference layer is 0.1-10 micrometers, It is more preferable that it is 0.5-5 micrometers, It is most preferable that it is 1-5 micrometers.

[Vertical Alignment Film]

In order to orientate the liquid crystal compound vertically on the alignment film side, it is important to lower the surface energy of the alignment film. Specifically, the surface energy of the alignment film is lowered by the functional group of the polymer, whereby the liquid crystal compound is made upright. As a functional group which reduces the surface energy of an oriented film, a fluorine atom and a hydrocarbon group with 10 or more carbon atoms are effective. In order to make a fluorine atom or a hydrocarbon group exist in the surface of an oriented film, it is preferable to introduce a fluorine atom or a hydrocarbon group into a side chain rather than a main chain of a polymer. It is preferable to contain a fluorine atom in the ratio of 0.05-80 mass%, It is more preferable to contain in the ratio of 0.1-70 mass%, It is still more preferable to contain a fluorine-containing polymer in the ratio of 0.5-65 mass%. It is most preferable to contain in the ratio of 1-60 mass%. The hydrocarbon group is an aliphatic group, an aromatic group or a combination thereof. The aliphatic group may be any of cyclic, branched or straight chain. The aliphatic group is preferably an alkyl group (which may be a cycloalkyl group) or an alkenyl group (which may be a cycloalkenyl group). The hydrocarbon group may have a substituent which does not exhibit strong hydrophilicity as the halogen atom. It is preferable that carbon number of a hydrocarbon group is 10-100, It is more preferable that it is 10-60, It is most preferable that it is 10-40. It is preferable that the main chain of a polymer has a polyimide structure or a polyvinyl alcohol structure.

Generally, a polyimide is synthesize | combined by the condensation reaction of tetracarboxylic acid and diamine. You may synthesize | combine the polyimide corresponded to a copolymer using two or more types of tetracarboxylic acids or two or more types of diamine. The fluorine atom or hydrocarbon group may exist in the repeating unit of tetracarboxylic acid origin, may exist in the repeating unit of diamine origin, and may exist in both repeating units. When introducing a hydrocarbon group into a polyimide, it is particularly preferable to form a steroid structure in the main chain or the side chain of the polyimide. The steroid structure present in the side chain corresponds to a hydrocarbon group having 10 or more carbon atoms, and has a function of vertically aligning the liquid crystalline compound. In the present specification, the steroid structure means a ring structure in which a cyclopentanohydrophenanthrene ring structure or a part of a bond of the ring is a double bond in the range of the aliphatic ring (the range not forming an aromatic ring).

Moreover, as a means of orienting a liquid crystalline compound vertically, the method of mixing an organic acid with the polymer of polyvinyl alcohol, modified polyvinyl alcohol, or polyimide can be used preferably. As the acid to be mixed, carboxylic acid, sulfonic acid and amino acid are preferably used. You may use what shows acidity among the air interface alignment agents mentioned later. It is preferable that it is 0.1 mass%-20 mass% with respect to a polymer, and, as for the mixing amount, it is more preferable that it is 0.5 mass%-10 mass%.

70-100% is preferable and, as for the saponification degree of the said polyvinyl alcohol, 80-100% is more preferable. It is preferable that the polymerization degree of polyvinyl alcohol is 100-5000.

When oriented a discotic liquid crystalline compound, it is preferable that an oriented film consists of a polymer which has a hydrophobic group as a functional group in a side chain. The kind of specific functional group is determined according to the kind of liquid crystalline molecule and the orientation state required. For example, the modified group of the modified polyvinyl alcohol can be introduced by copolymerization modification, chain transfer modification or block polymerization modification. Examples of the modified group include hydrophilic groups (carboxylic acid groups, sulfonic acid groups, phosphonic acid groups, amino groups, ammonium groups, amide groups, thiol groups), hydrocarbon groups having 10 to 100 carbon atoms, hydrocarbon groups substituted with fluorine atoms, thioether groups, and polymerizable properties. The group (unsaturated polymerizable group, epoxy group, adilinidyl, etc.), the alkoxy silyl group (trialkoxy, dialkoxy, monoalkoxy), etc. are mentioned. As a specific example of these modified polyvinyl alcohol compounds, Paragraph Nos. [0022]-[0145] in the specification of Unexamined-Japanese-Patent No. 2000-155216, Paragraph No. of [0018]-[ 0022] etc. can be mentioned.

An alignment film is formed using the polymer which has a side chain which has a crosslinkable functional group couple | bonded with the main chain, or the polymer which has a crosslinkable functional group in the side chain which has a function which orients a liquid crystalline molecule, and a retardation film is formed on it. When it forms using a composition, the polymer in an oriented film and the polyfunctional monomer in the retardation film formed on it can be copolymerized. As a result, covalent bonds are formed not only between the polyfunctional monomers, but also between the alignment film polymers and between the polyfunctional monomers and the alignment film polymers, and the alignment film and the retardation film are firmly bonded. Therefore, by forming the alignment film using a polymer having a crosslinkable functional group, the strength of the optical compensation sheet can be remarkably improved. It is preferable that the crosslinkable functional group of an oriented film polymer contains a polymeric group like a polyfunctional monomer. Specifically, the thing of Paragraph No. [0080]-[0100] etc. in the specification of Unexamined-Japanese-Patent No. 2000-155216 are mentioned, for example.

The alignment film polymer may be crosslinked using a crosslinking agent separately from the above crosslinkable functional groups. Examples of the crosslinking agent include aldehydes, N-methylol compounds, dioxane derivatives, compounds which act by activating a carboxyl group, active vinyl compounds, active halogen compounds, isoxazoles and dialdehyde starches. You may use together 2 or more types of crosslinking agents. Specifically, the compound of Paragraph No. 0023-0024 in Unexamined-Japanese-Patent No. 2002-62426 specification, etc. are mentioned, for example. Aldehydes having high reaction activity, particularly glutaraldehyde, are preferred.

0.1-20 mass% is preferable with respect to a polymer, and, as for the addition amount of a crosslinking agent, 0.5-15 mass% is more preferable. It is preferable that it is 1.0 mass% or less, and, as for the quantity of the unreacted crosslinking agent which remains in an oriented film, it is more preferable that it is 0.5 mass% or less. By adjusting in this way, even if it aligns an oriented film in a liquid crystal display device for a long period of time or in the atmosphere of high temperature, high humidity, long enough durability is obtained without the occurrence of reticulation.

An alignment film can be formed by apply | coating the composition containing the said polymer which is an alignment film formation material, and a crosslinking agent on a transparent support body fundamentally, and then heat-drying (crosslinking) and rubbing process. As mentioned above, after apply | coating on a transparent support body, you may perform a crosslinking reaction at arbitrary times. In the case of using a water-soluble polymer such as polyvinyl alcohol as the alignment film forming material, it is preferable that the coating liquid is a mixed solvent of an organic solvent having an antifoaming effect (for example, methanol) and water. The ratio is preferably 0: 100 to 99: 1, more preferably 0: 100 to 91: 9, in terms of mass ratio of water: methanol. Thereby, generation | occurrence | production of a bubble is suppressed and the defect of the surface of an oriented film, and also retardation layer is remarkably reduced.

The coating method of the alignment film is preferably a spin coating method, a dip coating method, a curtain coating method, an extrusion coating method, a rod coating method or a roll coating method. In particular, the rod coating method is preferable. Moreover, as for the film thickness after drying, 0.1-10 micrometers is preferable. Heat drying can be performed at 20 degreeC-110 degreeC. In order to form sufficient crosslinking, 60 to 100 degreeC is preferable, and 80 to 100 degreeC is especially preferable. Although drying time can be performed in 1 minute-36 hours, Preferably they are 1 minute-30 minutes. It is preferable to set pH also to an optimal value for the crosslinking agent to be used, and when glutaraldehyde is used, it is pH 4.5-5.5, Especially 5 is preferable.

It is preferable that an oriented film is formed on a transparent support body. The alignment film can be obtained by crosslinking the polymer layer as described above and then rubbing the surface.

The said rubbing process can apply the processing method employ | adopted widely as a liquid-crystal aligning process of LCD. That is, the method of obtaining an orientation can be used by rubbing the surface of an oriented film in a fixed direction using paper, a gauze, a felt, rubber or nylon, polyester fiber, etc. Generally, it carries out by rubbing about several times using the cloth etc. which averaged the fiber of uniform length and thickness, and the like.                     

In order to uniformly align the discotic liquid crystal compound, the orientation direction is preferably controlled by the rubbing treated vertical alignment film. On the other hand, it is preferable that the rubbing treatment is not performed on the vertical alignment of the rod-like liquid crystal compound. On the other hand, after orienting a liquid crystalline compound using an oriented film, you may fix a liquid crystalline compound in the orientation state, and form a phase difference layer, and only a phase difference layer may be transferred on a polymer film (or a transparent support body).

[Air Interface Alignment Agent]

Usually, since a liquid crystalline compound has the property to incline and orientate on the air interface side, in order to acquire the state uniformly vertically aligned, it is necessary to vertically control the liquid crystalline compound on the air interface side. For this purpose, it is preferable to form a retardation film by containing in the liquid crystal coating liquid a compound which is unevenly distributed on the air interface side and has a function of vertically aligning the liquid crystal compound by the exclusion volume effect or the electrostatic effect. In the discotic liquid crystal compound, the action of vertically aligning the liquid crystal compound corresponds to the action of reducing the inclination angle of the director, that is, the angle between the director and the coated liquid crystal air side surface. As a compound which reduces the inclination angle of the director of a discotic liquid crystal molecule, the polymer containing the rigid structural unit which has an exclusion volume effect like the maleimide group represented by following General formula (1) is used preferably. Moreover, by mix | blending these compounds, applicability | paintability improves and generation | occurrence | production of nonuniformity or abrasion is suppressed.                     

General formula (1)

In Formula (1), A represents the repeating unit represented by following General formula (2), B represents the repeating unit derived from an ethylenically unsaturated monomer, a and b are the mass percentage which shows a copolymerization ratio, and a is 1- 100 mass% and b represent the numerical value of 0-99 mass%.

General formula (2)

In Formula (2), X, X <^1>, and X <^2> respectively independently represent a hydrogen atom or a substituent.

When more specifically described, in the general formula (2) include a group of the following substituent represented by X, X ¹ and X ^2.

Alkyl group (preferably an alkyl group having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably 1 to 8 carbon atoms, for example, methyl group, ethyl group, isopropyl group, tert-butyl group, n- Octyl group, n-decyl group, n-hexadecyl group, cyclopropyl group, cyclopentyl group, cyclohexyl group, etc. are mentioned, Alkenyl group (preferably C2-C20, More preferably, C2-C20) 12, Especially preferably, as a C2-C8 alkenyl group, a vinyl group, an aryl group, 2-butenyl group, 3-pentenyl group, etc. are mentioned, for example, Alkynyl group (preferably C2-C8) 20, More preferably, it is a C2-C12, Especially preferably, as an alkynyl group of C2-C8, a propargyl group, 3-pentynyl group, etc. are mentioned, An aryl group (preferably C6-C6) To 30, more preferably an aryl group having 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms. For example, a phenyl group, a 2, 6- diethylphenyl group, a 3, 5- ditrifluoromethylphenyl group, a naphthyl group, a biphenyl group etc. are mentioned, A substituted or unsubstituted amino group (preferably carbon number 0) It is -20, More preferably, as an amino group of 0-10 carbon atoms, Especially preferably, a C0-C6 amino group, Unsubstituted amino group, a methylamino group, a dimethylamino group, a diethylamino group, an anilino group, etc. are mentioned. ),

Alkoxy group (preferably C1-C20, More preferably, it is C1-C10, Especially preferably, it is C1-C6, For example, a methoxy group, an ethoxy group, butoxy group etc. are mentioned), Alkoxy Carbonyl group (preferably C2-C20, More preferably, it is C2-C10, Especially preferably, it is 2-6, For example, a methoxycarbonyl group, an ethoxycarbonyl group, etc. are mentioned), Acyloxy group ( Preferably it is C2-C20, More preferably, it is C2-C10, Especially preferably, it is 2-6, For example, an acetoxy group, a benzoyloxy group, etc. are mentioned, Acylamino group (preferably C2-C20, More preferably, it is C2-C10, Especially preferably, it is C2-C6, For example, an acetylamino group, a benzoylamino group, etc. are mentioned, The alkoxycarbonylamino group (preferably C2-C20) 20, more preferred Crab is C2-C10, Especially preferably, it is C2-C6, For example, a methoxycarbonylamino group etc. are mentioned, An aryloxycarbonylamino group (preferably C7-20, More preferably, it is more preferable) Preferably it is C6-C16, Especially preferably, it is C4-C12, For example, a phenyloxycarbonylamino group etc. are mentioned, A sulfonylamino group (Preferably C1-C20, More preferably, C1-C20) 1-10, Especially preferably, it is C1-C6, For example, a methanesulfonylamino group, a benzenesulfonylamino group, etc. are mentioned, A sulfamoyl group (preferably C0-20, More preferably, Carbon number 0-10, Especially preferably, it is C6-C6, For example, a sulfamoyl group, a methyl sulfamoyl group, a dimethyl sulfamoyl group, a phenyl sulfamoyl group, etc. are mentioned, Carbamoyl group (preferably Is 1 to 20 carbon atoms, more preferably Carbon atoms and from 1 to 10, and particularly preferably having 1 to 6 carbon atoms, for example, be no substitutions carbamoyl, methyl carbamoyl, diethyl carbamoyl group, phenyl carbamoyl group, etc.),

Alkylthio group (preferably C1-C20, More preferably, it is C1-C10, Especially preferably, it is C1-C6, For example, a methylthio group, an ethylthio group, etc. are mentioned), Aryl Thio (preferably C6-C20, More preferably, it is C6-C16, Especially preferably, it is 6-12, For example, a phenylthio group etc. are mentioned), A sulfonyl group (Preferably C1-C1) -20, More preferably, it is C1-C10, Especially preferably, it is C1-C6, For example, a mesyl group, a tosyl group, etc. are mentioned, A sulfinyl group (Preferably 1-20, Preferably Is C1-C10, Especially preferably, it is C1-C6, For example, methane sulfinyl group, a benzene sulfinyl group, etc. are mentioned, A ureide group (preferably C1-C20, More preferably, 1 to 10 carbon atoms, particularly preferably 1 to 6 carbon atoms, for example, unsubstituted And a lauryl group, a methyl ureide group, a phenyl uraide group, and the like, a phosphate amide group (preferably, having 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, and particularly preferably 1 to 6 carbon atoms). For example, a diethyl phosphate amide group, a phenyl phosphate amide group, etc. can be mentioned), a hydroxyl 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 sulphate Aeration, carboxyl group, nitro group, hydroxy group, sulfino group, hydrazino group, imino group, heterocyclic group (preferably a heterocyclic group having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, for example, Heterocyclic group which has hetero atoms, such as a nitrogen atom, an oxygen atom, and a sulfur atom, For example, an imidazolyl group, a pyridyl group, a quinolyl group, a furyl group, a piperidyl group, a morpholino group, a benzooxazolyl group, Benzimidazolyl Group, Benzthiazolyl Group And silyl groups (preferably, C3-C40, More preferably, it is C3-C30, Especially preferably, it is C3-C24 silyl group, For example, a trimethylsilyl group and a triphenyl Silyl groups, etc.) are included.

These substituents may also be substituted by these substituents. In addition, when it has two or more substituents, they may be the same and may differ. In addition, if possible, they may be bonded to each other to form a ring.

X is preferably a hydrogen atom, a substituted or unsubstituted alkyl group (including a cycloalkyl group) or an aryl group, particularly preferably a substituted or unsubstituted alkyl group (including a cycloalkyl group) or an aryl group, most preferably Is an aryl group. X ¹ and X ² are each independently, preferably a hydrogen atom, a halogen atom or a substituted or unsubstituted alkyl group, particularly preferably a hydrogen atom or a substituted or unsubstituted alkyl group, and most preferably a hydrogen atom .

In said general formula (1), B is a repeating unit (henceforth "repeating unit B") derived from at least 1 type of ethylenically unsaturated monomer (henceforth "monomer B"), and the monomer group illustrated below It is preferable that it is a repeating unit derived from the repeating unit derived from 1 sort (s) chosen from or the copolymer which combined 2 or more types independently and freely chosen from the following monomer groups. There is no restriction | limiting in particular in the monomer which can be used, If a normal radical polymerization reaction is possible, it can use preferably.

Monomer group

(1) alkenes

Ethylene, propylene, 1-butene, isobutene, 1-hexene, 1-dodecene, 1-octadecene, 1-icocene, hexafluoropropene, vinylidene fluoride, chlorotrifluoroethylene, 3,3, 3-trifluoropropylene, tetrafluoroethylene, vinyl chloride, vinylidene chloride and the like;

(2) dienes

1,3-butadiene, isoprene, 1,3-pentadiene, 2-ethyl-1,3-butadiene, 2-n-propyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2 -Methyl-1,3-pentadiene, 1-phenyl-1,3-butadiene, 1-α-naphthyl-1,3-butadiene, 1-β-naphthyl-1,3-butadiene, 2-chloro- 1,3-butadiene, 1-bromo-1,3-butadiene, 1-chlorobutadiene, 2-fluoro-1,3-butadiene, 2,3-dichloro-1,3-butadiene, 1,1,2 -Trichloro-1,3-butadiene and 2-cyano-1,3-butadiene, 1,4-divinylcyclohexane and the like;

(3) derivatives of α, β-unsaturated carboxylic acids

(3a) alkyl acrylates

Methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, amyl acrylate, n-hexyl acryl Latex, cyclohexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, tert-octyl acrylate, dodecyl acrylate, phenyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, 2-bromo Ethyl acrylate, 4-chlorobutyl acrylate, 2-cyanoethyl acrylate, 2-acetoxyethyl acrylate, methoxybenzyl acrylate, 2-chlorocyclohexyl acrylate, furfuryl acrylate, tetrahydrofurfuryl Acrylate, 2-methoxyethylacrylate, ω-methoxypolyethyleneglycolacrylate (addition moles of polyoxyethylene: n = 2 to 1 00), 3-methoxybutylacrylate, 2-ethoxyethylacrylate, 2-butoxyethylacrylate, 2- (2-butoxyethoxy) ethylacrylate, 1-bromo-2- Methoxyethyl acrylate, 1,1-dichloro-2-ethoxyethyl acrylate, glycidyl acrylate, etc.);

(3b) Alkyl methacrylates

Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, Amyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, stearyl methacrylate, benzyl methacrylate, phenyl methacrylate, Allyl methacrylate, furfuryl methacrylate, tetrahydrofurfuryl methacrylate, credil methacrylate, naphthyl methacrylate, 2-methoxyethyl methacrylate, 3-methoxybutyl methacrylate, ω -Methoxypolyethylene glycol methacrylate (addition moles of polyoxyethylene: n = 2 to 100), 2-acetoxyethyl methacrylate, 2-ethoxyethyl methacrylate, 2-part Cyethyl methacrylate, 2- (2-butoxyethoxy) ethyl methacrylate, glycidyl methacrylate, 3-trimethoxysilylpropyl methacrylate, allyl methacrylate, 2-isocyanate ethyl methacrylate Rate and the like;

(3c) diesters of unsaturated polyhydric carboxylic acids

Dimethyl maleate, dibutyl maleate, dimethyl itaconic acid, dibutyl itaconic acid, dibutyl crotonate, dihexyl crotonate, diethyl fumarate, dimethyl fumarate and the like;

(3d) Amides of α, β-unsaturated carboxylic acids

N, N-dimethyl acrylamide, N, N-diethyl acrylamide, Nn-propyl acrylamide, N-tert butyl acrylamide, N-tert octyl methacrylamide, N-cyclohexyl acrylamide, N-phenyl acrylamide N- (2-acetoacetoxyethyl) acrylamide, N-benzyl acrylamide, N-acryloyl morpholine, diacetone acrylamide, N-methyl maleimide, and the like;

(4) unsaturated nitriles

Acrylonitrile, methacrylonitrile and the like;

(5) styrene and its derivatives                     

Styrene, vinyltoluene, ethylstyrene, p-tertbutylstyrene, methyl p-vinylbenzoate, α-methylstyrene, p-chloromethylstyrene, vinylnaphthalene, p-methoxystyrene, p-hydroxymethylstyrene, p-ace Oxy styrene and the like;

(6) vinyl esters

Vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl benzoate, vinyl salicylate, vinyl chloroacetate, methoxyvinyl acetate, vinyl phenyl acetate and the like;

(7) vinyl ethers

Methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, tert-butyl vinyl ether, n-pentyl vinyl ether, n-hexyl vinyl ether, n- Octyl vinyl ether, n-dodecyl vinyl ether, n-eicosyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexyl vinyl ether, fluorobutyl vinyl ether, fluorobutoxyethyl vinyl ether, etc .;

(8) other polymerizable monomers

N-vinylpyrrolidone, methyl vinyl ketone, phenyl vinyl ketone, methoxy ethyl vinyl ketone, 2-vinyl oxazoline, 2-isopropenyl oxazoline, and the like.

In General Formula (1), it is preferable that B contains at least one repeating unit represented by the following General Formula (3).                     

General formula (3)

In formula (3), R <^1> , R <^2> and R <^3> respectively independently represents the group represented by a hydrogen atom, an alkyl group, a halogen atom, or -LQ. L represents a divalent linking group, and Q represents an alkyl group or a polar group having hydrogen bonding.

In formula (3), R <^1> , R <^2> and R <^3> are respectively independently a hydrogen atom, an alkyl group, a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.) or -LQ mentioned later. It is group represented, Preferably it is a hydrogen atom, a C1-C6 alkyl group, a chlorine atom, group represented by -LQ, More preferably, it is a hydrogen atom, a C1-C4 alkyl group, Especially preferably, a hydrogen atom, It is a C1-C2 alkyl group. Specific examples of the alkyl group include methyl group, ethyl group, n-propyl group, n-butyl group, sec-butyl group and the like. The alkyl group may have a suitable substituent. Examples of the substituent include a halogen atom, an aryl group, a heterocyclic group, an alkoxyl group, an aryloxy group, an alkylthio group, an arylthio group, an acyl group, a hydroxyl group, an acyloxy group, an amino group, an alkoxycarbonyl group, an acylamino group, an oxycarbonyl group, Carbamoyl group, sulfonyl group, sulfamoyl group, sulfonamide group, sulfonyl group, carboxyl group and the like.

In addition, carbon number of an alkyl group does not contain the carbon atom of a substituent. The same applies to the carbon number of other groups below.

L is preferably a group selected from the following linking group, or a divalent linking group formed by combining two or more thereof.

(Connector group)

Single bond, -O-, -CO-, -NR ^4- (R ⁴ represents a hydrogen atom, an alkyl group, an aryl group or an aralkyl group), -S-, -SO _2- , -P (= O) (OR ⁵ )-(R ⁵ represents an alkyl group, an aryl group, or an aralkyl group), an alkylene group and an arylene group.

As L, it is preferable to include a single bond, -O-, -CO-, -NR ^4- , -S-, -SO _2- , an alkylene group or an arylene group, and -CO-, -O-, -NR ⁴ -, more preferably containing an alkylene group or arylene group, and, -CO-, -O-, -NR ⁴ - is more preferable, which includes, or alkylene group.

When L contains an alkylene group, carbon number of an alkylene group becomes like this. Preferably it is 1-10, More preferably, it is 1-8, Especially preferably, it is 1-6. Methylene, ethylene, trimethylene, tetrabutylene, hexamethylene group, etc. are mentioned as an example of especially preferable alkylene group.

When L contains an arylene group, carbon number of an arylene group becomes like this. Preferably it is 6-24, More preferably, it is 6-18, Especially preferably, it is 6-12. As a specific example of an especially preferable arylene group, a phenylene, a naphthalene group, etc. are mentioned.

When L contains the bivalent coupling group (that is, aralkylene group) obtained by combining an alkylene group and an arylene group, carbon number of an aralkylene group becomes like this. Preferably it is 7-34, More preferably, it is 7-26, Especially Preferably it is 7-16. As a specific example of an especially preferable aralkylene group, a phenylene methylene group, a phenylene ethylene group, a methylene phenylene group, etc. are mentioned.

The group mentioned as L may have a suitable substituent. As a substituent for the substituent as the first R ¹ ~ R ³ it can be given to all substituents and machangajiin.

Although the specific structure of L is illustrated below, this invention is not limited to these specific examples.

The polar group having a hydrogen bondability represented by Q is preferably a salt of a hydroxyl group, a carboxyl group, or a carboxyl group (for example, lithium salt, sodium salt, potassium salt, ammonium salt (for example, ammonium, tetramethylammonium, trimethyl-2- Hydroxyethylammonium, tetrabutylammonium, trimethylbenzylammonium, dimethylphenylammonium, etc.), pyridinium salts, etc.), amides of carboxylic acids (N unsubstituted or N-mono lower alkyl substituents, for example -CONH ₂ , -CONHCH ₃ Etc.), sulfo groups, salts of sulfo groups (examples of cations forming salts), sulfonamide groups (N unsubstituted or N-mono lower alkyl substituents, -SO ₂ NH ₂ , -SO ₂ NHCH ₃ etc.), phospho groups, salts of phospho groups (examples of cations that form salts are as described above in the carboxyl groups), phosphonamides (N unsubstituted or N-mono lower alkyl substituents, eg -OP (= O) (NH ₂ ) ₂ , -OP (= O) (N HCH ₃ ) _2, etc.), a ureide group (-NHCONH ₂ ), an amino group in which the N position is unsubstituted or mono-substituted (-NH ₂ , -NHCH ₃ ), and the like (where the lower alkyl group represents a methyl group or an ethyl group). More preferably, it is a hydroxyl group, a carboxyl group, a sulfo group, or a phospho group, Especially preferably, it is a hydroxyl group or a carboxyl group.

The alkyl group represented by Q is preferably 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably an alkyl group having 1 to 8 carbon atoms. For example, a methyl group, an ethyl group, an isopropyl group, or a butyl group and tert-butyl group, n-octyl group, n-decyl group, n-hexadecyl group, cyclopropyl group, cyclopentyl group, cyclohexyl group and the like.

1 type may be independent of the said repeating unit A and B contained in the polymer represented by the said General formula (1), and 2 or more types of repeating units A and B may exist simultaneously. It is preferable that B is comprised with 2 or more types of repeating units which a hydroxyl group and a carboxyl group exist simultaneously, and it is most preferable that B is comprised with 3 or more types of repeating units which a hydroxyl group, a carboxyl group, and an alkyl group exist simultaneously.

a is 1-100 mass%, b is a numerical value of 0-99 mass%, Preferably a is 5-100 mass%, b is 0-95 mass%, More preferably, a is 10-100 mass%. , b is 0 to 90 mass%, particularly preferably a is 30 to 100 mass% and b is 0 to 70 mass% or more. Since the numerical value of a preferable range fluctuates easily according to the molecular weight of the monomer to be used, said mass percentage can express exactly content of a repeating unit by the mole number of functional groups per unit mass of a polymer. When the above notation is used, the polymer of the present invention preferably contains 0.1 mmol / g to 10 mmol / g of hydrogen-bonding polar group, and contains 0.2 mmol / g to 8 mmol / g of hydrogen-bonding polar group. Is particularly preferred.

Although it does not specifically limit about the polymerization method for manufacturing the polymer represented by the said General formula (1), For example, polymerization methods, such as cation polymerization, radical polymerization, or anionic polymerization using a vinyl group, can be used, Among these, radical polymerization is particularly preferable in that it can be used for general purposes.

As a polymerization initiator of radical polymerization, although well-known compounds, such as a radical thermal polymerization initiator and a radical photoinitiator, can be used, it is especially preferable to use a radical thermal polymerization initiator. Here, a radical thermal polymerization initiator is a compound which generate | occur | produces a radical by heating above decomposition temperature. As such a radical thermal polymerization initiator, For example, diacyl peroxide (acetyl peroxide, benzoyl peroxide etc.), ketone peroxide (methyl ethyl ketone peroxide, cyclohexanone peroxide etc.), hydroperoxide (hydrogen peroxide, tert- Butyl hydroperoxide, cumene hydroperoxide, etc.), dialkyl peroxide (di-tert-butyl peroxide, dicumyl peroxide, dilauroyl peroxide, etc.), peroxy esters (tert-butyl peroxy acetate, tert) -Butyl peroxy pivalate, etc.), an azo compound (azobisisobutyronitrile, azobisisovaleronitrile, etc.), persulfates (ammonium persulfate, sodium persulfate, potassium persulfate, etc.) are mentioned. These radical thermal polymerization initiators may be used individually by 1 type, or may be used in combination of 2 or more type.

The radical polymerization method is not particularly limited, and it is possible to use an emulsion polymerization method, a suspension polymerization method, a bulk polymerization method, a solution polymerization method and the like. More specifically, solution polymerization, which is a typical radical polymerization method, will be described. The outline of the other polymerization methods is the same, and the details thereof are described in, for example, "Polymer Science Experiment Method" Polymer Society Review (Tokyo Chemical Co., 1981).

In order to perform solution polymerization, an organic solvent is used. These organic solvents can be arbitrarily selected in the range which does not impair the objective and effect of this invention. These organic solvents are normally organic compounds which have a value within the range whose boiling point is 50-200 degreeC under atmospheric pressure, and the organic compound which melt | dissolves each structural component uniformly is preferable. Examples of preferred organic solvents include alcohols such as isopropanol and butanol, dibutyl ether, ethylene glycol dimethyl ether, tetrahydrofuran and ethers such as dioxane, acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexa Ketones such as rice fields, esters such as ethyl acetate, butyl acetate, amyl acetate and γ-butyrolactone, and aromatic hydrocarbons such as benzene, toluene, and xylene. In addition, these organic solvents can be used individually by 1 type or in combination of 2 or more types. Moreover, the water-mixed organic solvent which used water together with the said organic solvent is also applicable from the viewpoint of the solubility of a monomer and the polymer to produce | generate.

Moreover, although solution polymerization conditions are not specifically limited, For example, it is preferable to heat for 10 minutes-30 hours within the temperature range of 50-200 degreeC. In addition, it is preferable to perform an inert gas purge not only during solution polymerization but also before solution polymerization is started so that the generated radicals are not deactivated. As an inert gas, nitrogen gas is normally used preferably.

In order to obtain the polymer of this invention in the preferable molecular weight range, the radical polymerization method using a chain transfer agent is especially effective.

Examples of the chain transfer agent include mercaptans (eg, octyl mercaptan, decyl mercaptan, dodecyl mercaptan, tert-dodecyl mercaptan, octadecyl mercaptan, thiophenol, p-nonylthiophenol, and the like), and polyhalogenated alkyls. (For example, carbon tetrachloride, chloroform, 1,1,1-trichloroethane, 1,1,1-tribromooctane, etc.), low activity monomers (α-methylstyrene, α-methylstyrene dimer, etc.) Although either may be used, Preferably it is a C4-C16 mercaptans. The amount of these chain transfer agents is significantly influenced by the activity of the chain transfer agent, the combination of the monomers, the polymerization conditions, and the like, and precise control is necessary, but is usually about 0.01 mol% to 50 mol% based on the total moles of the monomers used. , Preferably it is 0.05 mol%-30 mol%, Especially preferably, it is 0.08 mol%-25 mol%. These chain transfer agents should just exist in a system simultaneously with the target monomer which should control a polymerization degree in superposition | polymerization process, and it does not mind in particular about the addition method. It may melt | dissolve and add to a monomer and can also add separately from a monomer.

 It is preferable that the mass mean molecular weight of the polymer represented by General formula (1) of this invention is 1,000,000 or less. More preferably, the mass average molecular weight is 500,000 or less, and particularly preferably the mass average molecular weight is 100,000 or less. A mass average molecular weight can be measured as a polyethylene oxide (PEO) conversion value using gel permeation chromatography (GPC).

Although the specific example of the polymer represented by General formula (1) which can be preferably used by this invention below is shown, this invention is not limited to these specific examples. The numerical value in a formula shows a mass percentage which shows the composition ratio of each monomer, respectively, and Mw shows the mass mean molecular weight of PEO conversion measured by GPC.

In addition to the exemplified compounds, the compounds described in JP-A-2002-20363 and JP-A-2002-129162 can be used as the air interfacial alignment agent. Further, paragraphs [0072] to [0075] of the specification of Japanese Patent Application No. 2002-212100, paragraphs [0037] to [0039] of the specification of Japanese Patent Application 2002-262239, and paragraphs of the specification of Japanese Patent Application 2003-91752 No. [0071] to [0078], paragraphs [0052] to [0054], [0065] to [0066], [0092] to [0094] of Japanese Patent Application No. 2003-119959, and Japanese Patent Application No. 2003-330303 The matters described in paragraphs [0028] to [0030] of the call specification can also be appropriately applied to the present invention.

It is preferable that the usage-amount of the air interface aligning agent with respect to a liquid crystal coating liquid is 0.05 mass%-5 mass%. Moreover, when using a fluorine-type air interface aligning agent, it is preferable that it is 1 mass% or less.

[Other compositions of phase difference layer]

A plasticizer, surfactant, a polymerizable monomer, etc. can be used together with the said liquid crystalline compound, and the uniformity of a coating film, the intensity | strength of a film, the orientation of a liquid crystalline compound, etc. can be improved. It is preferable that these materials have compatibility with a liquid crystalline compound, and do not inhibit orientation.

A radically polymerizable or cationically polymerizable compound is mentioned as a polymerizable monomer. Preferably it is a polyfunctional radically polymerizable monomer, and it is preferable that it is copolymerizable with the liquid crystal compound containing the said polymeric group. For example, the thing of Paragraph No. [0018]-[0020] in Unexamined-Japanese-Patent No. 2002-296423 specification is mentioned. It is preferable that the addition amount of the said compound exists in the range of 1-50 mass% with respect to a disk shaped liquid crystalline molecule generally, and exists in the range of 5-30 mass%.

Although a conventionally well-known compound is mentioned as surfactant, Especially a fluorine-type compound is preferable. Specifically, for example, the compounds described in paragraphs [0028] to [0056] in the specification of JP 2001-330725, and paragraphs [0069] to [0126] in the specification of JP 2003-295212 The compound described is mentioned.

It is preferable that the polymer used with a liquid crystalline compound can thicken a coating liquid. As an example of a polymer, a cellulose ester is mentioned. As a preferable example of a cellulose ester, the thing of Paragraph No. in the Unexamined-Japanese-Patent No. 2000-155216 specification is mentioned. It is preferable to exist in the range of 0.1-10 mass% with respect to a liquid crystalline molecule, and, as for the addition amount of the said polymer, in order not to inhibit the orientation of a liquid crystalline compound, it is more preferable to exist in the range which is 0.1-8 mass%. 70-300 degreeC is preferable and, as for the discotic nematic liquid crystal phase-solid-state transition temperature of a liquid crystalline compound, 70-170 degreeC is more preferable.

[Support]

In the present invention, a transparent support can also be used. As a transparent support body, it is preferable to use the polymer film with small wavelength dispersion. It is also preferable that the transparent support is small in optical anisotropy. Transparent support means that the light transmittance is 80% or more. Specifically, it is preferable that the ratio of Re400 / Re700 is less than 1.2 that wavelength dispersion is small. Specifically, it is preferable that in-plane retardation (Re) is 20 nm or less, and, as for an optical anisotropy is small, it is more preferable that it is 10 nm or less. Examples of the polymer include cellulose esters, polycarbonates, polysulfones, polyethersulfones, polyacrylates and polymethacrylates. Cellulose ester is preferable, acetyl cellulose is more preferable, and triacetyl cellulose is the most preferable. It is preferable to form a polymer film by the solvent cast method. It is preferable that it is 20-500 micrometers, and, as for the thickness of a transparent support body, it is more preferable that it is 50-200 micrometers. In order to improve the adhesion between the transparent support and the layer (adhesive layer, vertical alignment layer or retardation layer) formed thereon, the transparent support is subjected to surface treatment (e.g., glow discharge treatment, corona discharge treatment, ultraviolet (UV) treatment, flame treatment). You may carry out. An adhesive layer (undercoat) may be formed on the transparent support. On the other hand, in order to give sliding property in a conveyance process to a transparent support body and a long transparent support body, or to prevent adhesion | attachment of the back surface and the surface after winding, the inorganic particle whose average particle diameter is about 10-100 nm is 5% by solid content weight ratio. It is preferable to use the thing which formed the polymer layer which mixed -40% by one side of the support body by coating or covalent edge with a support body.

[Protective film for 2nd polarizing plate]

As a protective film for 2nd polarizing plates, it is preferable that there is no absorption in visible region, light transmittance is 80% or more, and small retardation based on birefringence is small. Specifically, in-plane Re is preferably 0 to 20 nm, more preferably 0 to 10 nm, and most preferably 0 to 5 nm. Moreover, it is preferable that retardation Rth of a thickness direction is 0-40 nm, 0-20 nm is more preferable, It is most preferable that it is 0-10 nm. Although it can use preferably if it is a film which has this characteristic, From a viewpoint of the durability of a polarizing film, a cellulose acetate and norbornene-type film are more preferable. As a method of making Rth of a cellulose acetate film small, the method of Unexamined-Japanese-Patent No. 11-246704, 2001-247717, Japan Patent Application 2003-379975, etc. are mentioned. Moreover, Rth can be made small also by making the thickness of a cellulose acetate film small. It is preferable that it is 10-60 micrometers, and, as for the thickness of the cellulose acetate film as a protective film for 2nd polarizing plates, it is more preferable that it is 20-45 micrometers.

[Example]

The features of the present invention will be described in more detail with reference to Examples and Comparative Examples. The materials, usage amounts, ratios, treatment contents, treatment procedures, and the like shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be limitedly interpreted by the specific example shown below.

Example 1

<Production of IPS Mode Liquid Crystal Cell 1>

On one glass substrate, as shown in FIG. 1, electrodes (2 and 3 in FIG. 1) are arrange | positioned so that the distance between adjacent electrodes may be 20 micrometers, a polyimide film is formed as an orientation film on it, and a rubbing process is performed. It was. The rubbing process was performed in the direction 4 shown in FIG. A polyimide film was formed on one surface of one glass substrate separately prepared, and a rubbing treatment was performed to obtain an alignment film. The two glass substrates are arranged so that the alignment films are opposed to each other so that the substrate has a gap (gap) of 3.9 μm and the rubbing directions of the two glass substrates are parallel to each other, so that the refractive anisotropy (Δn) is 0.0769 and A dielectric liquid crystal composition having a dielectric constant anisotropy (Δε) of 4.5 was encapsulated. The value of d? Δn of the liquid crystal layer was 300 nm.

<Production of Optical Compensation Film 1>

(Production of the First Retardation Region)

The following composition was put into the mixing tank, it stirred while heating, each component was melt | dissolved, and the cellulose acetate solution which has the following composition was prepared.

Composition of Cellulose Acetate Solution

100 parts by mass of cellulose acetate having an acetylation degree of 60.9%

Triphenyl phosphate (plasticizer) 7.8 parts by mass

Biphenyl diphenyl phosphate (plasticizer) 3.9 parts by mass

300 parts by mass of methylene chloride (first solvent)

Methanol (second solvent) 54 parts by mass

11 parts by mass of 1-butanol (third solvent)

16 mass parts of following retardation increasing agents, 80 mass parts of methylene chloride, and 20 mass parts of methanol were thrown into another mixing tank, and it stirred, heating, and prepared the retardation increasing agent solution. 7 mass parts of retardation increasing agent solutions were mixed with 487 mass parts of cellulose acetate solutions, and it fully stirred, and dope was prepared.

Retardation synergist

The obtained dope was cast using a band softener. After the film surface temperature on the band became 40 degreeC, it dried for 1 minute by 60 degreeC warm air, and peeled the film from the band. Next, the film was dried for 10 minutes by a 140 degreeC dry wind, and the cellulose acetate film 1 of thickness 80micrometer was produced.

The optical properties of this film were obtained by measuring the light incidence angle dependence of Re using an automatic birefringence meter (KOBRA-21ADH, manufactured by Oji Measurement Instruments Co., Ltd.), where Re = 8 nm and Rth = 82 nm. .

(Production of the second phase difference region)

After saponifying the surface of the said cellulose acetate film 1, 20 mL / m <2> of aligning-film application liquids of the following composition were apply | coated on this film with the wire bar coater. It dried for 60 second by the warm air of 60 degreeC, and 120 second by the warm air of 100 degreeC again, and formed the film | membrane. Next, the formed film was subjected to a rubbing treatment in a direction parallel to the slow axis direction of the film to form an alignment film.

Composition of alignment film coating liquid                     

10 parts by mass of the following modified polyvinyl alcohol

371 parts by mass of water

119 parts by mass of methanol

Glutaraldehyde 0.5 parts by mass

0.3 parts by mass of paratoluenesulfonic acid

Modified polyvinyl alcohol

Next, on the alignment film, 1.8 g of the following discotic liquid crystalline compounds, ethylene oxide modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.), a photopolymerization initiator (Ilgacua 907, Chiba) The solution which melt | dissolved 0.06 g of Gaiji company, 0.02 g of sensitizers (made by Kayakyu DETX, Nippon Kayaku Co., Ltd.), and 0.01 g of air interface side vertical alignment agents (example compound P-6) in 3.9 g of methyl ethyl ketone , # 3.4 wire bar was applied. This was adhere | attached to the metal mold | die, and it heated for 3 minutes in 125 degreeC thermostat, and orientated the discotic liquid crystal compound. Next, UV irradiation was carried out for 30 seconds at 120 ° C. using a high pressure mercury lamp at 100 ° C. to crosslink the discotic liquid crystal compound. Thereafter, the mixture was allowed to cool to room temperature. In this way, the optical compensation film 1 was produced.                     

Discotic Liquid Crystal Compound

By measuring the light incidence angle dependency of Re of the optical compensation film 1 using an automatic birefringence meter (KOBRA-21ADH, manufactured by Oji Measurement Instruments Co., Ltd.), and subtracting the contribution of the cellulose acetate film measured in advance, When the optical properties of only the discotic liquid crystal retardation layer were calculated, it was confirmed that Re was 130 nm, Rth was -65 nm, and the average inclination angle of the liquid crystal was 89.9 °, and the discotic liquid crystal was oriented perpendicular to the film plane. . In addition, the direction of the slow axis was parallel to the rubbing direction of the alignment film.

Iodine was adsorbed on the stretched polyvinyl alcohol film to prepare a polarizing film. Using the polyvinyl alcohol adhesive, the produced optical compensation film 1 was adhered to one side of the polarizing film so that the cellulose acetate film was on the polarizing film side. The transmission axis of the polarizing film and the slow axis of the optical compensation film (the slow axis of the second retardation region also coincided with this) were arranged to be parallel. A commercially available cellulose acetate film (Fuji Tak TD80UF, manufactured by Fuji Shashin Film Co., Ltd., thickness of 80 μm, Re = 3 nm, Rth = 45 nm) was subjected to saponification treatment, and the polyvinyl alcohol-based adhesive was used on the opposite side of the polarizing film. Adhered to. On the one side of the IPS mode liquid crystal cell 1 produced above, the slow axis of the optical compensation film 1 is parallel to the rubbing direction of the liquid crystal cell (that is, the ground axis of the second retardation region is the liquid crystal cell at the time of black display). Parallel to the slow axis of the liquid crystal molecules), and the discotic liquid crystal coated surface side was bonded so as to be the liquid crystal cell side. Subsequently, a commercially available polarizing plate (HLC2-5618, manufactured by Sanlitz Co., Ltd.) was bonded to the other side of the IPS mode liquid crystal cell 1 in a cross nicol arrangement to produce a liquid crystal display device.

<Measurement of leaked light of manufactured liquid crystal display device>

The leakage light of the liquid crystal display device thus produced was measured. The leakage light when observed from the left inclined direction 70 ° was 0.12%.

[Example 2]

<Production of Optical Compensation Film 2>

As the first retardation region, a commercially available cellulose acetate film (Fujitak TD80UF, manufactured by Fuji Shashin Film Co., Ltd., thickness of 80 µm, Re = 3 nm, Rth = 45 nm) was used to saponify the surface thereof. 20 ml / m <2> of the coating liquid of the same orientation film as Example 1 with this wire bar coater on this film. Applied. It dried for 60 second by the warm air of 60 degreeC, and 120 second by the warm air of 100 degreeC, and formed the film | membrane. Next, the rubbing process was performed to the formed film in the direction parallel to the slow axis direction of a film, and the alignment film was obtained.

Subsequently, 1.8 g of the discotic liquid crystalline compound used in Example 1, 0.2 g of ethylene oxide-modified trimethylolpropane triacrylate (V # 360, made by Osaka Organic Chemical Co., Ltd.), and a photoinitiator (ilgacua) were used on the alignment film. 0.090 g of 907, Chiba Chemical Co., Ltd., the sensitizer (Kayakyua DETX, Nippon Kayaku Co., Ltd.) 0.02 g, the solution which melt | dissolved the following air interface side vertical aligning agent 0.003 g in 3.9 g of methyl ethyl ketone # 3 wire bars were applied. This was adhere | attached to the metal mold | die, and it heated for 3 minutes in 125 degreeC thermostat, and orientated the discotic liquid crystal compound. Next, 120 W / cm high pressure mercury lamp was used at 100 degreeC, UV irradiation was carried out for 30 second, and the discotic liquid crystal compound was bridge | crosslinked. Thereafter, the mixture was allowed to cool to room temperature. In this way, the optical compensation film 2 was produced.

Air interface side vertical aligning agent: Exemplary compound (32) described in Japanese Patent Laid-Open No. 2002-129162

By using an automatic birefringence meter (KOBRA-21ADH, manufactured by Oji Measurement Instruments Co., Ltd.), the light incidence angle dependency of Re of the optical compensation film 2 was measured, and the contribution of the measured cellulose acetate film was measured. When the optical characteristics of only the tick liquid crystal retardation layer were calculated, it was confirmed that Re was 115 nm, Rth was -57 nm, and the average inclination angle of the liquid crystal was 89.9 degrees, and the discotic liquid crystal was oriented perpendicular to the film plane. In addition, the direction of the slow axis was parallel to the rubbing direction of the alignment film.

On one side of the IPS mode liquid crystal cell 1 produced above, the optical compensation sheet 2 produced above is placed so that its slow axis is parallel to the rubbing direction of the liquid crystal cell (that is, the slow axis of the second retardation region is displayed in black). And the discotic liquid crystal coating surface side were bonded to the liquid crystal cell side. Subsequently, a commercially available polarizing plate (HLC2-5618, manufactured by Sanlitz Co., Ltd.) was bonded on the optical compensation sheet 2 so that the transmission axis was parallel to the rubbing direction of the liquid crystal cell. The same polarizing plate was adhere | attached on the other side by the cross nicol arrangement, and the liquid crystal display device was produced.

(Measurement of leakage light of manufactured liquid crystal display device)

The leakage light of the liquid crystal display device thus produced was measured. The leakage light when observed from the left inclined direction 70 ° was 0.13%.

Example 3

<Production of Second Polarizer 1>

Using a commercially available cellulose acetate film (Fuji Tak TD80UF, manufactured by Fuji Shashin Film Co., Ltd., thickness of 80 µm, Re = 3 nm, Rth = 45 nm), the surface saponification treatment was carried out, and commercially available on this film Diluted vertical alignment film (JALS-204R, manufactured by Nippon Synthetic Rubber Co., Ltd.) 1: 1 with methyl ethyl ketone, and then 2.4 ml / m 2 with a wire bar coater. Applied. Immediately, drying was performed for 120 seconds with a warm air of 120 ° C.

(Formation of Vertically Oriented Bar Liquid Crystal Compound Layer)

On the alignment film, 1.8 g of the following rod-shaped liquid crystal compound, 0.06 g of a photopolymerization initiator (manufactured by Ilgacua 907, manufactured by Chiba Co., Ltd.), sensitizer (Kayakyua DETX, manufactured by Nippon Kayaku Co., Ltd.), and the following air interface side vertical The solution which melt | dissolved 0.002 g of aligning agents in 9.2 g of methyl ethyl ketone was apply | coated with the wire bar of # 2. This was adhere | attached on the metal mold | die, and it heated for 2 minutes in the thermostat of 100 degreeC, and oriented the rod-shaped liquid crystal compound. Next, 120 W / cm high pressure mercury lamp was used at 100 degreeC, UV irradiation was carried out for 30 second, and the rod-shaped liquid crystal compound was bridge | crosslinked. Thereafter, the mixture was allowed to cool to room temperature. In this way, the protective film 1 of the 2nd polarizing plate was produced.

Rod-shaped liquid crystal compound

Air interface side vertical alignment agent:

Exemplary compound (II-4) described in Japanese Patent Application No. 2003-119959

When the light incident angle dependence of Re of the protective film 1 was measured using the automatic birefringence meter (KOBRA-21ADH, the product made by Oji Measurement Instruments Co., Ltd.), Re was 3 nm and Rth was 5 nm.

Next, iodine was adsorbed to the stretched polyvinyl alcohol film to produce a polarizing film, and the produced protective film 1 was bonded to one side of the polarizing film so that the cellulose acetate film was on the polarizing film side using a polyvinyl alcohol-based adhesive. Subsequently, a saponification process was performed to the commercially available cellulose acetate film (Fujitax TD80UF, manufactured by Fuji Shashin Film Co., Ltd.), and was adhered to the opposite side of the polarizing film using a polyvinyl alcohol-based adhesive to form a second polarizing plate. . Moreover, the 1st polarizing plate which bonded the optical compensation film 1 to one side of a polarizing film so that a cellulose acetate film may become a polarizing film side, and adhered the commercially available cellulose acetate film to the opposite side of a polarizing film like Example 1 was formed. On one side of the IPS mode liquid crystal cell 1 produced in Step 1, the slow axis of the optical compensation film 1 is parallel to the rubbing direction of the liquid crystal cell (that is, the slow axis of the second retardation region is the ground of the liquid crystal molecules at the time of black display). Parallel to the axial direction), and the discotic liquid crystal coating surface side was bonded so as to be the liquid crystal cell side. The transmission axis of this polarizing plate and the rubbing direction of a liquid crystal cell are parallel. Moreover, the 2nd polarizing plate was adhere | attached on the other side of this liquid crystal cell so that the transmission axis might become orthogonal to the rubbing direction of a liquid crystal cell, and the protective film 1 surface side was a liquid crystal cell side, and the liquid crystal display device was produced.

(Measurement of leakage light of manufactured liquid crystal display device)

The leakage light of the liquid crystal display device thus produced was measured. The leakage light when observed from the left inclined direction 70 ° was 0.03%.

Example 4

Iodine was adsorbed on the stretched polyvinyl alcohol film to prepare a polarizing film. A commercially available cellulose acetate film (Fuji Tak T40UZ, manufactured by Fuji Shashin Film Co., Ltd., thickness 40 μm, Re = 1 nm, Rth = 35 nm) was subjected to a saponification treatment on both sides of this polarizing film with a polyvinyl alcohol-based adhesive. It bonded by using and the polarizing plate was produced. A liquid crystal display device was produced in the same manner as in Example 3 except that the polarizing plate was used as the second polarizing plate.

(Measurement of leakage light of manufactured liquid crystal display device)

The leakage light of the liquid crystal display device thus produced was measured. The leakage light when observed from the left inclined direction 70 ° was 0.09%.

Comparative Example 1

A commercially available polarizing plate (HLC2-5618, manufactured by Sanlitz Co., Ltd.) was bonded to both sides of the produced IPS mode liquid crystal cell 1 in a batch of cross nicol to prepare a liquid crystal display device. No optical compensation film was used. In the said liquid crystal display device, the polarizing plate was adhere | attached so that the transmission axis of an upper polarizing plate might be parallel to the rubbing direction of a liquid crystal cell like Example 1. The leakage light of the liquid crystal display device thus produced was measured. The leakage light when observed from the left inclined direction 70 ° was 0.55%.

Comparative Example 2

Adhesion of the optical compensation sheet 2 produced in Example 2 to the IPS mode liquid crystal cell 1 produced in Example 1 so that its slow axis is perpendicular to the rubbing direction of the liquid crystal cell, and the discotic liquid crystal coated surface side is the liquid crystal cell side. It was. Subsequently, a commercially available polarizing plate (HLC2-5618, manufactured by Sanlitz Co., Ltd.) was bonded on the optical compensation sheet 2 so that the transmission axis was parallel to the rubbing direction of the liquid crystal cell, and the other side of the IPS mode liquid crystal cell 1 The same polarizing plate was bonded by the side of cross nicol to the side of, and the liquid crystal display device was produced. The leakage light of the liquid crystal display device thus produced was measured. The leakage light when observed from the left inclined direction 70 ° was very large at 1.52%.

According to the present invention, it is possible to provide an IPS type liquid crystal display device in which not only the display quality but also the viewing angle is remarkably improved with a simple configuration.

Claims (10)

An optical compensation film comprising a first polarizing film, a first retardation region in contact with the first polarizing film, and a second retardation region overlapping the first retardation region, a first substrate, and a liquid crystal layer made of a liquid crystal material; An IPS type liquid crystal display device in which a second substrate is arranged in this order and liquid crystal molecules of the liquid crystal material are oriented parallel to the surfaces of the pair of substrates at the time of black display. Using the in-plane refractive indices nx and ny (nx ≥ny), the refractive index nz in the thickness direction, and the film thickness d Re = (nx-ny) × d In-plane retardation Re of the 1st phase difference region defined by is 8 nm or less, and Rth = ((nx + ny) / 2-nz) × d The retardation Rth in the thickness direction of the first retardation region defined by is 20 nm to 120 nm, and the second retardation region is formed by polymerizing a polymerizable composition containing a discotic liquid crystal compound and a polymerizable initiator, and is substantially vertical. An oriented discotic liquid crystal compound, the slow axis of the second retardation region is parallel to the transmission axis of the first polarizing film and the slow axis direction of the liquid crystal molecules at the time of black display, The ratio of Re400 / Re700 of the first retardation region is less than 1.2, Re of the second retardation region is 50 nm to 200 nm, The first retardation region is composed of a plurality of layers, the layer in contact with the second retardation region among the plurality of layers is an alignment film, and the second retardation region is at least a discotic liquid crystal compound and discotic liquid crystal at the air interface side. An IPS type liquid crystal display device comprising an air interface alignment agent for reducing the inclination angle of the director of the compound. delete delete The IPS type liquid crystal display device according to claim 1, wherein the first retardation region is composed of a plurality of layers, and a layer in contact with the first polarizing film among the plurality of layers functions as a protective film of the first polarizing film. The IPS type liquid crystal display device according to claim 1, further comprising a second polarizing film on an outer side of said second substrate. The IPS type liquid crystal display according to claim 5, having a pair of protective films arranged with the second polarizing film interposed therebetween, and the phase difference Rth in the thickness direction of the protective film on the side closer to the liquid crystal layer among the pair of protective films being 40 nm or less. Device. The IPS type liquid crystal display according to claim 6, having a pair of protective films arranged with the second polarizing film interposed therebetween, and the phase difference Rth in the thickness direction of the protective film on the side closer to the liquid crystal layer among the pair of protective films being 20 nm or less. Device. The IPS type liquid crystal display device according to claim 5, wherein the IPS type liquid crystal display device has a pair of protective films disposed with the second polarizing film interposed therebetween, and the thickness of the protective film on the side close to the liquid crystal layer among the pair of protective films is 10 to 60 µm. The IPS type liquid crystal display device according to claim 5, wherein, among the pair of protective films arranged with the second polarizing film interposed therebetween, the protective film close to the liquid crystal layer is a cellulose acetate film or a norbornene-based film. The IPS type according to claim 5, wherein, among the pair of protective films arranged with the second polarizing film interposed therebetween, the protective film on the side close to the liquid crystal layer has a layer containing a rod-like liquid crystal compound vertically aligned with the cellulose acetate film. Liquid crystal display.

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