JP2005321528A - Liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an IPS (in-plane switching) liquid crystal display with significantly improved display quality and a viewing angle. <P>SOLUTION: The liquid crystal display comprises a liquid crystal cell having a first polarizing film, a first retardation region, a second retardation region and a liquid crystal layer all interposed between a pair of substrates, and a second polarizing film, in which the liquid crystal molecules are aligned parallel to the surface of the substrate during black display. Retardation Re in the first retardation region defined by Re=(nx-ny)×d using the refractive indices nx, ny (nx≥ny) in the plane, the refractive index nz in the thickness direction and the film thickness d ranges 60 to 200 nm. A value Nz defined by Nz=(nx-nz)/(nx-ny) is in the range over 0.8 to 1.5 or less. The first retardation region has a retardation layer obtained by stretching an alicyclic structure-containing polymer resin film. The refractive indices nx and ny in the plane in the second retardation region are substantially equal to each other, and retardation Rth in the thickness direction in the second retardation region defined by Rth=ä(nx+ny)/2-nz}×d ranges -200 to -50 nm. The transmission axis of the first polarizing film is parallel to the slow phase axis of the liquid crystal molecules during black display. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid crystal display device, and more particularly to an in-plane switching mode liquid crystal display device that performs display by applying a horizontal electric field to liquid crystal molecules aligned in a horizontal direction.

  As a liquid crystal display device, a so-called TN mode is widely used in which a liquid crystal layer in which nematic liquid crystal is twisted is sandwiched between two orthogonal polarizing plates and an electric field is applied in a direction perpendicular to the substrate. In this system, since the liquid crystal rises with respect to the substrate during black display, birefringence occurs due to liquid crystal molecules when viewed from an oblique direction, and light leakage occurs. To solve this problem, a system for optically compensating the liquid crystal cell and preventing this light leakage by using a film in which liquid crystal molecules are hybrid-aligned has been put into practical use. However, even if liquid crystal molecules are used, it is very difficult to completely optically compensate the liquid crystal cell without any problem, resulting in a problem that gradation reversal in the lower direction of the screen cannot be suppressed.

  In order to solve such a problem, a liquid crystal display device using a so-called in-plane switching (IPS) mode in which a lateral electric field is applied to the liquid crystal, or a liquid crystal having a negative dielectric anisotropy is vertically aligned in the panel. A vertical alignment (VA) mode in which alignment is divided by protrusions and slit electrodes has been proposed and put into practical use. In recent years, these panels have been developed not only for monitor applications but also for TV applications, and screen brightness has been greatly improved accordingly. For this reason, slight light leakage in the diagonally oblique incidence direction during black display, which has not been considered as a problem in these operation modes, has become apparent as a cause of deterioration in display quality.

  As one means for improving the color tone and the viewing angle of black display, the arrangement of an optical compensation material having birefringence characteristics between the liquid crystal layer and the polarizing plate is also studied in the IPS mode. For example, by arranging a birefringent medium having an optical axis orthogonal to each other to compensate for the increase / decrease in retardation of the liquid crystal layer during tilting, a white display or a halftone display is diagonally arranged between the substrate and the polarizing plate. It is disclosed that coloring can be improved when viewing directly from (see Patent Document 1). In addition, a method using an optical compensation film made of a styrenic polymer having a negative intrinsic birefringence or a discotic liquid crystalline compound (see Patent Documents 2, 3, and 4), or an optical axis having a positive birefringence as an optical compensation film. A film in which the film is in the plane of the film and a film having a positive birefringence and an optical axis in the normal direction of the film (see Patent Document 5), biaxial optical compensation with a retardation of half wavelength A method using a sheet (see Patent Document 6), a method using a film having a negative retardation as a protective film of a polarizing plate, and providing an optical compensation layer having a positive retardation on this surface (see Patent Document 7) Proposed.

Japanese Patent Laid-Open No. 9-80424 Japanese Patent Laid-Open No. 10-54982 JP-A-11-202323 Japanese Patent Laid-Open No. 9-292522 JP 11-133408 A JP-A-11-305217 JP-A-10-307291

  However, many of the proposed methods are methods that improve the viewing angle by canceling the birefringence anisotropy of the liquid crystal in the liquid crystal cell, so the polarization axis crossing angle when the orthogonal polarizing plate is viewed from an oblique direction. There is a problem that the light leakage based on the deviation from orthogonality cannot be solved sufficiently. Even in a system that can compensate for this light leakage, it is very difficult to completely optically compensate the liquid crystal cell without any problem. Furthermore, in the optical compensation sheet for an IPS mode liquid crystal cell that performs optical compensation with a stretched birefringent polymer film, it is necessary to use a plurality of films. As a result, the thickness of the optical compensation sheet is increased, and the display device is made thinner. It is disadvantageous. In addition, since an adhesive layer is used for laminating stretched films, the adhesive layer contracts due to changes in temperature and humidity, and defects such as peeling and warping between films may occur.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an IPS liquid crystal display device with a simple configuration and not only display quality but also a viewing angle that is remarkably improved.

  Many of the proposed methods require a complicated manufacturing process in order to adjust the optical direction (optical axis or slow axis). For example, it is necessary to manufacture a chip obtained by cutting an optical compensation sheet at a predetermined angle by so-called “batch sticking”, in which a chip is bonded and laminated with an adhesive. In the manufacturing method, the quality is likely to be deteriorated due to the shaft misalignment, and there is a high possibility that the yield is reduced and the manufacturing cost is increased.

  The present invention has been made in view of the above problems, and firstly, an object is to provide an IPS liquid crystal display device in which not only display quality but also a viewing angle is remarkably improved. A second object of the present invention is to provide an IPS liquid crystal display device that is excellent in stability of optical characteristics, can be manufactured by a roll-to-roll method, and has excellent production efficiency.

Means for solving the above-mentioned problems are as follows.
(1) At least a first polarizing film, a first retardation region, a second retardation region, a liquid crystal cell having a liquid crystal layer sandwiched between a pair of substrates, and a second polarizing film, A liquid crystal display device in which liquid crystal molecules of a liquid crystal layer are aligned parallel to the surfaces of the pair of substrates,
Using the in-plane refractive indices nx and ny (nx ≧ ny), the refractive index nz in the thickness direction, and the thickness d of the film, the first retardation region defined by Re = (nx−ny) × d Retardation Re is 60 nm to 200 nm,
The value Nz of the first phase difference region defined by Nz = (nx−nz) / (nx−ny) exceeds 0.8 and is 1.5 or less.
The first retardation region has a retardation layer obtained by stretching an alicyclic structure-containing polymer resin film,
In-plane refractive indices nx and ny are substantially equal, nx <nz, and the thickness of the second retardation region defined by Rth = {(nx + ny) / 2−nz} × d. A liquid crystal display device in which the direction retardation Rth is -200 nm to -50 nm and the transmission axis of the first polarizing film is parallel to the slow axis direction of the liquid crystal molecules during black display.
(2) The first polarizing film, the first retardation region, the second retardation region, and the liquid crystal cell are arranged in this order, and the slow axis of the first retardation region is the transmission axis of the first polarizing film. The liquid crystal display device according to (1), which is substantially parallel.
(3) The first polarizing film, the second retardation region, the first retardation region, and the liquid crystal cell are arranged in this order, and the slow axis of the first retardation region is substantially the transmission axis of the first polarizing film. (1) The liquid crystal display device which is orthogonal to
(4) The liquid crystal display device according to any one of (1) to (3), wherein the retardation layer of the first retardation region is a long stretched film obtained by stretching a norbornene-based film.

(5) having a pair of protective films arranged with at least one of the first polarizing film and the second polarizing film interposed therebetween, and at least the position in the thickness direction of the protective film on the side close to the liquid crystal layer of the pair of protective films The liquid crystal display device according to any one of (1) to (4), wherein the phase difference Rth is 40 nm to -50 nm.
(6) It has a pair of protective films arranged with at least one of the first polarizing film and the second polarizing film interposed therebetween, and at least the position of the protective film on the side close to the liquid crystal layer in the thickness direction of the pair of protective films The liquid crystal display device according to any one of (1) to (4), wherein the phase difference Rth is 20 nm to -20 nm.
(7) It has a pair of protective films arranged with at least one of the first polarizing film and 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 60 μm or less. The liquid crystal display device according to any one of (1) to (6).
(8) Ratio Re (450) / Re (750) of the retardation layer of the first retardation region between the in-plane letter with a wavelength of 450 nm and the in-plane retardation Re (750) with a wavelength of 750 nm. ) Is less than 1.1. The liquid crystal display device according to any one of (1) to (7).
(9) The liquid crystal display device according to any one of (1) to (8), wherein the slow axis of the first retardation region is ± 5 ° or 90 ° ± 5 ° with respect to the transmission axis of the first polarizing film.
(10) It has a pair of protective films arranged with the first polarizing film and the second polarizing film interposed therebetween, and at least the protective film on the side close to the liquid crystal layer is a cellulose acylate film or a norbornene-based film The liquid crystal display device according to any one of (1) to (9), comprising a film.

  According to the present invention, the contrast decreases due to the shift of the absorption axes of the two polarizing plates from 90 degrees when viewed from an oblique azimuth direction without changing the characteristics in the front direction, particularly 45 degrees. It is possible to improve the decrease in contrast from the oblique direction and the change in the viewing angle of the color during black display.

BEST MODE FOR CARRYING OUT THE INVENTION

  In the following, one embodiment of the liquid crystal display device of the present invention and its constituent members will be sequentially described. In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

  In the present specification, “parallel” and “orthogonal” mean that the angle is within a range of strictly less than ± 10 °. In this range, an error from a strict angle is preferably less than ± 5 °, and more preferably less than ± 2 °. Further, the “slow axis” means a direction in which the refractive index is maximized. Further, the measurement wavelengths of the refractive index and the phase difference are values at λ = 550 nm in the visible light region unless otherwise specified.

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

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing an example of a pixel region of the liquid crystal display device of the present invention. 2 and 3 are schematic views of an embodiment of the liquid crystal display device of the present invention.
[Liquid Crystal Display]
The liquid crystal display device shown in FIG. 2 is a liquid crystal comprising polarizing films 8 and 20, a first retardation region 10, a second retardation region 12, a pair of substrates 13 and 17, and a liquid crystal layer 15 sandwiched between the substrates. Cell. The polarizing films 8 and 20 are sandwiched between protective films 7a and 7b and 19a and 19b, respectively.

  In the liquid crystal display device of FIG. 2, the liquid crystal cell includes substrates 13 and 17 and a liquid crystal layer 15 sandwiched between them. The product Δn · d of the thickness d (μm) of the liquid crystal layer and the refractive index anisotropy Δn is optimal in the range of 0.2 to 0.4 μm for the IPS type having no twisted structure in the transmission mode. In this range, the white display luminance is high and the black display luminance is small, so that a bright and high-contrast display device can be obtained. An alignment film (not shown) is formed on the surfaces of the substrates 13 and 17 that are in contact with the liquid crystal layer 15 to align liquid crystal molecules substantially parallel to the surface of the substrate and to be rubbed on the alignment film. By the processing directions 14 and 18 and the like, the liquid crystal molecule alignment direction in the voltage non-application state or the low application state is controlled, and the direction of the slow axis 16 is determined. Further, an electrode (not shown in FIG. 2) capable of applying a voltage to the liquid crystal molecules is formed on the inner surface of the substrate 13 or 17.

FIG. 1 schematically shows the alignment of liquid crystal molecules in one pixel region of the liquid crystal layer 15. FIG. 1 shows the alignment of liquid crystal molecules in a very small area corresponding to one pixel of the liquid crystal layer 15 in the rubbing direction 4 of the alignment film formed on the inner surfaces of the substrates 13 and 17 and the substrates 13 and 17. It is the schematic diagram shown with the electrodes 2 and 3 which can apply a voltage to the liquid crystal molecule formed in the inner surface. When active driving is performed using a nematic liquid crystal having positive dielectric anisotropy as a field effect liquid crystal, the liquid crystal molecule alignment directions in a no voltage application state or a low application state are 5a and 5b. A display is obtained. When applied between the electrodes 2 and 3, the liquid crystal molecules change their alignment direction in the directions of 6 a and 6 b in accordance with the voltage. Usually, bright display is performed in this state.
The liquid crystal cell used in the present invention is not limited to the IPS mode, and any liquid crystal display device in which liquid crystal molecules are aligned substantially parallel to the surfaces of the pair of substrates during black display can be used. It can be used suitably. Examples thereof include a ferroelectric liquid crystal display device, an antiferroelectric liquid crystal display device, and an ECB type liquid crystal display device.

  In FIG. 2 again, the transmission axis 9 of the polarizing film 8 and the transmission axis 21 of the polarizing film 20 are arranged orthogonally. Further, the slow axis 11 of the first phase difference region 10 is arranged in parallel with the transmission axis 9 of the polarizing film 8. Further, the transmission axis 9 of the polarizing film 8 and the slow axis 16 of the liquid crystal molecules in the liquid crystal layer 14 at the time of black display are parallel, that is, the slow axis 11 of the first retardation region 10 and the liquid crystal black display. The slow axis 16 of the liquid crystal layer 14 at the time is parallel. The first retardation region 10 is a stretched film produced by stretching a film made of an alicyclic structure-containing polymer resin. In order to satisfy the optical characteristics described later, the first retardation region 10 may be a laminate with other stretched films, or an optical anisotropy exhibiting an optical anisotropy expressed by the orientation of the liquid crystalline compound. It may be a laminate with layers. In this aspect, the first retardation region 10 having specific optical characteristics to be described later is arranged in this manner, and the second retardation region 13 having specific optical characteristics to be described later is replaced with the first retardation region 10 and the liquid crystal. By disposing it between the cells, the viewing angle characteristics of the liquid crystal cell are improved.

  In the liquid crystal display device shown in FIG. 2, the configuration in which the polarizing film 8 is sandwiched between the two protective films 7a and 7b is shown, but the protective film 7b may be omitted. However, when the protective film 7b is not disposed, the first retardation region 10 needs to have a specific optical characteristic to be described later and also have a function of protecting the polarizing film 8. When the protective film 7b is disposed, the thickness direction retardation Rth of the protective film is preferably −50 nm to 40 nm, and more preferably −20 nm to 20 nm. Further, although the polarizing film 20 is also sandwiched between the two protective films 19a and 19b, the protective film 19a on the side close to the liquid crystal layer 15 may be omitted. When the protective film 19a is disposed, the thickness direction retardation Rth of the protective film is preferably −50 nm to 40 nm, and more preferably −20 nm to 20 nm. Moreover, it is preferable that the thickness of the protective film 7b and the protective film 19a is thin, and specifically, it is preferable that it is 60 nm or less.

  In the embodiment of FIG. 2, the first retardation region and the second retardation region may be disposed between the liquid crystal cell and the viewing-side polarizing film with reference to the position of the liquid crystal cell. May be disposed between the liquid crystal cell and the polarizing film on the back side, but it is preferable in terms of yield to be disposed between the liquid crystal cell and the polarizing film on the back side. In either embodiment, the second phase difference region is disposed closer to the liquid crystal cell in the configuration of FIG.

  Another embodiment of the present invention is shown in FIG. 3, the same members as those in FIG. 2 are denoted by the same reference numerals, and detailed description thereof is omitted. In the liquid crystal display device shown in FIG. 3, the positions of the first retardation region 10 and the second retardation region 12 are interchanged, and the first retardation region 10 is separated from the polarizing film 8 compared to the second retardation region 12. It is arranged at a position farther away, that is, a position closer to the liquid crystal cell. In the embodiment shown in FIG. 3, the first retardation region 10 is arranged such that its slow axis 11 is orthogonal to the transmission axis 9 of the polarizing film 8. Further, the transmission axis 9 of the polarizing film 8 and the slow axis 16 of the liquid crystal molecules in the liquid crystal layer 14 at the time of black display are parallel, that is, the slow axis 11 of the first retardation region 10 and the liquid crystal black display. The slow axis 16 of the liquid crystal layer 14 at the time is orthogonal. In this aspect, the first retardation region 10 having specific optical characteristics to be described later is arranged in this manner, and the second retardation region having specific optical characteristics to be described later is arranged as the first retardation region 10 and the polarizing film 8. The viewing angle characteristics of the liquid crystal cell are improved.

  In the liquid crystal display device of FIG. 3 as well, the protective film 7b or the protective film 19a may be omitted as described above. However, when the protective film 7 b is not provided, the second retardation region 12 needs to have a specific optical characteristic to be described later and also have a function of protecting the polarizing film 8. When the protective film 7b is disposed, the thickness direction retardation Rth of the protective film is preferably −50 nm to 40 nm, and more preferably −20 nm to 20 nm. Further, although the polarizing film 20 is also sandwiched between the two protective films 19a and 19b, the protective film 19a on the side close to the liquid crystal layer 15 may be omitted. When the protective film 19a is disposed, the thickness direction retardation Rth of the protective film is preferably −50 nm to 40 nm, and more preferably −20 nm to 20 nm. Moreover, it is preferable that the thickness of the protective film 7b and the protective film 19a is thin, and specifically, it is preferable that it is 60 nm or less.

  In the aspect of FIG. 3, the first retardation region and the second retardation region may be disposed between the liquid crystal cell and the viewing-side polarizing film with reference to the position of the liquid crystal cell. Although it may be arranged between the liquid crystal cell and the polarizing film on the back side, it is preferable in terms of yield to be arranged between the liquid crystal cell and the polarizing film on the back side. In any aspect, in the configuration of FIG. 3, the first phase difference region is arranged closer to the liquid crystal cell.

  The liquid crystal display device of the present invention is not limited to the configuration shown in FIGS. 1 to 3 and may include other members. For example, a color filter may be disposed between the liquid crystal layer and the polarizing film. Further, an antireflection treatment or a hard coat may be applied to the surface of the protective film of the polarizing film. Moreover, you may use what gave electroconductivity to the structural member. In the case of use as a transmission type, a cold cathode or a hot cathode fluorescent tube, or a backlight having a light emitting diode, a field emission element, or an electroluminescent element as a light source can be disposed on the back surface. In this case, the arrangement of the backlight may be on the upper side or the lower side in FIGS. 2 and 3, but the necessity of combining with a polarizing plate subjected to antireflection or antistatic treatment with a slightly high defective product rate is low. Therefore, it is more preferable to lower the backlight in the figure. In addition, a reflective polarizing plate, a diffusion plate, a prism sheet, or a light guide plate can be disposed between the liquid crystal layer and the backlight. Further, as described above, the liquid crystal display device of the present invention may be of a reflection type. In such a case, only one polarizing plate may be disposed on the observation side, and the back side of the liquid crystal cell or the lower side of the liquid crystal cell. A reflective film is disposed on the inner surface of the substrate. Of course, it is also possible to provide a 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. The present invention is particularly effective when applied to an active matrix liquid crystal display device using a three-terminal or two-terminal semiconductor element such as TFT or MIM. Of course, a mode applied to a passive matrix liquid crystal display device called time-division driving is also effective.

  Hereinafter, preferred optical characteristics of various members usable in the liquid crystal display device of the present invention, materials used for the members, manufacturing methods thereof, and the like will be described in detail.

[First phase difference region]
In the present invention, the first retardation region is represented by Re = (nx−ny) × using in-plane refractive indices nx and ny (nx ≧ ny), a refractive index nz in the thickness direction, and a film thickness d. The retardation Re defined by d is 60 nm to 200 nm. In order to effectively reduce the light leakage in the oblique direction, Re of the first phase difference region is more preferably 70 nm to 180 nm, and further preferably 90 nm to 160 nm. Further, Nz defined by Nz = (nx−nz) / (nx−ny) is preferably more than 0.8 and 1.5 or less in order to effectively reduce light leakage in an oblique direction. Nz in the first retardation region is preferably 0.9 to 1.3, and more preferably 0.95 to 1.2. If it is 0.8 or less, Re required for improving the contrast becomes too large, the allowable range of the bonding angle with the polarizing plate becomes narrow, and the yield decreases, which is not preferable. On the other hand, if it exceeds 1.5, the Rth of the second retardation region necessary for improving the contrast becomes large, which is not preferable.

  The first retardation region is a retardation film having a retardation layer obtained by stretching an alicyclic structure-containing polymer resin film. The first retardation region may be an embodiment in which the retardation layer is laminated or a laminate with another stretched film, or an optical anisotropy formed from a composition containing a liquid crystalline compound. It may be a laminate with layers.

The alicyclic structure-containing polymer resin has an alicyclic structure in the repeating unit of the polymer resin, and a polymer resin having an alicyclic structure in the main chain and an alicyclic structure in the side chain. Any polymer resin can be used.
Examples of the alicyclic structure include a cycloalkane structure and a cycloalkene structure, and a cycloalkane structure is preferable from the viewpoint of thermal stability. Although there is no restriction | limiting in particular in carbon number which comprises an alicyclic structure, Usually, 4-30 pieces, Preferably it is 5-20 pieces, More preferably, it is 6-15 pieces. When the number of carbon atoms constituting the alicyclic structure is within this range, a stretched film having excellent heat resistance and flexibility can be obtained.

  The proportion of the repeating unit having an alicyclic structure in the polymer resin having an alicyclic structure may be appropriately selected according to the purpose of use, but is usually 50% by mass or more, preferably 70% by mass or more. Preferably it is 90 mass% or more. If the number of repeating units having an alicyclic structure is too small, the heat resistance is undesirably lowered. In addition, repeating units other than the repeating unit which has an alicyclic structure in an alicyclic structure containing polymer resin are suitably selected according to the intended purpose.

  Specific examples of the alicyclic structure-containing polymer resin include (1) norbornene polymer, (2) monocyclic olefin polymer, (3) cyclic conjugated diene polymer, and (4) vinyl alicyclic. Examples thereof include hydrocarbon polymers and hydrides (1) to (4). Among these, from the viewpoint of excellent heat resistance and mechanical strength, a norbornene polymer hydride, a vinyl alicyclic hydrocarbon polymer, and a hydride thereof are preferable, and a hydride of a norbornene polymer is more preferable.

The norbornene-based polymer used in the present invention is a single monomer mainly composed of norbornene-based monomers such as norbornene and its derivatives, tetracyclododecene and its derivatives, dicyclopentadiene and its derivatives, methanotetrahydrofluorene and its derivatives. Body polymer.
Specific examples of the norbornene-based polymer include (1) a ring-opening polymer of a norbornene-based monomer, and (2) a ring-opening copolymer of the norbornene-based monomer and other monomers copolymerizable therewith. (3) addition polymer of norbornene monomer, (4) addition polymer of norbornene monomer and other monomer copolymerizable therewith, and (1) to (4) A hydride etc. are mentioned.

  Examples of the norbornene-based monomer include bicyclo [2.2.1] hept-2-ene (common name: norbornene), tricyclo [4.3.0.12,5] deca-3,7-diene ( Common name: dicyclopentadiene), 7,8-benzotricyclo [4.3.0.12,5] dec-3-ene (common name: methanotetrahydrofluorene), tetracyclo [4.4.0.12, 5.17,10] dodec-3-ene (common name: tetracyclododecene), and derivatives of these compounds (for example, those having a substituent in the ring). Here, examples of the substituent include an alkyl group, an alkylene group, an alkoxycarbonyl group, and a carboxyl group. Moreover, these substituents may be the same or different and a plurality may be bonded to the ring. Norbornene monomers can be used alone or in combination of two or more.

  Examples of other monomers copolymerizable with norbornene monomers include, for example, monocyclic olefins such as cyclohexene, cycloheptene, and cyclooctene and derivatives thereof; cyclic conjugated dienes such as cyclohexadiene and cycloheptadiene and derivatives thereof And so on.

A ring-opening polymer of a norbornene monomer and a ring-opening copolymer with another monomer copolymerizable with the norbornene monomer are used in the presence of a ring-opening polymerization catalyst. It can be obtained by polymerization.
As the ring-opening polymerization catalyst to be used, for example, a catalyst comprising a metal halide such as ruthenium or osmium and a sulfate or acetylacetone compound and a reducing agent; or a metal halide such as titanium, zirconium, tungsten or molybdenum Or a catalyst comprising an acetylacetone compound and an organoaluminum compound;

  Norbornene monomer addition polymers and addition copolymers with other monomers copolymerizable with norbornene monomers can be obtained by polymerizing the monomers in the presence of an addition polymerization catalyst. Can do. As the addition polymerization catalyst, for example, a catalyst composed of a metal compound such as titanium, zirconium, vanadium and an organoaluminum compound can be used.

  Examples of other monomers that can be addition copolymerized with a norbornene monomer include ethylene, propylene, 1-butene, 1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1 Α-olefins having 2 to 20 carbon atoms such as hexadecene, 1-octadecene, 1-eicocene and derivatives thereof; cyclobutene, cyclopentene, cyclohexene, cyclooctene, 3a, 5,6,7a-tetrahydro-4,7-methano Cycloolefins such as -1H-indene and derivatives thereof; non-conjugated dienes such as 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, 1,7-octadiene, etc. Is mentioned. These monomers can be used alone or in combination of two or more. Among these, α-olefin is preferable and ethylene is more preferable.

Examples of the monocyclic olefin polymer used in the present invention include addition polymers such as cyclohexene, cycloheptene, and cyclooctene.
Examples of the cyclic conjugated diene polymer used in the present invention include polymers obtained by 1,2-addition polymerization or 1,4-addition polymerization of cyclic conjugated diene monomers such as cyclopentadiene and cyclohexadiene. it can.

  The molecular weight of the norbornene-based polymer, the monocyclic olefin polymer and the cyclic conjugated diene polymer is appropriately selected according to the purpose of use, but cyclohexane (toluene if the polymer resin does not dissolve) is used as the solvent. Polyisoprene or polystyrene-equivalent weight average molecular weight (Mw) measured by gel permeation chromatography, usually 10,000 to 100,000, preferably 25,000 to 80,000, more preferably 25,000 to 50,000. When the weight average molecular weight is in such a range, the mechanical strength and moldability of the film are highly balanced and suitable.

  The vinyl alicyclic hydrocarbon polymer is a polymer having a repeating unit derived from vinylcycloalkane or vinylcycloalkene. Examples of vinyl alicyclic hydrocarbon polymers include polymers of vinyl alicyclic hydrocarbon compounds such as vinyl cycloalkanes such as vinyl cyclohexane and vinyl cycloalkenes such as vinyl cyclohexene and their hydrides; styrene, α-methyl Examples include hydrides of aromatic moieties of polymers of vinyl aromatic hydrocarbon compounds such as styrene.

  The vinyl alicyclic hydrocarbon polymer is a random copolymer of a vinyl alicyclic hydrocarbon compound or a vinyl aromatic hydrocarbon compound and another monomer copolymerizable with these monomers, It may be a copolymer such as a block copolymer and a hydride thereof. Examples of block copolymerization include diblock, triblock, or more multiblock and gradient block copolymerization, but there is no particular limitation.

  The molecular weight of the vinyl alicyclic hydrocarbon polymer is appropriately selected according to the purpose of use, but it is measured by gel permeation chromatography using cyclohexane (toluene when the polymer resin does not dissolve) as a solvent. When the weight average molecular weight in terms of isoprene or polystyrene is usually in the range of 10,000 to 300,000, preferably 15,000 to 250,000, more preferably 20,000 to 200,000, It is suitable because the mechanical strength and moldability are highly balanced.

  Ring-opening polymer of norbornene-based monomer, ring-opening copolymer of norbornene-based monomer and other monomers capable of ring-opening copolymerization, addition polymer of norbornene-based monomer, norbornene-based Addition polymer of monomer and other monomer copolymerizable therewith, polymer of vinyl alicyclic hydrocarbon compound, aromatic part of polymer of vinyl aromatic hydrocarbon compound, vinyl alicyclic Hydrides of copolymers of the formula hydrocarbon compounds and vinyl aromatic hydrocarbon compounds with other monomers copolymerizable with these monomers, such as nickel, palladium, etc. It can obtain by adding the well-known hydrogenation catalyst containing these transition metals, and hydrogenating a carbon-carbon unsaturated bond preferably 90% or more.

  The glass transition temperature of the alicyclic structure-containing polymer resin used in the present invention may be appropriately selected according to the purpose of use, but is preferably 80 ° C. or higher, more preferably in the range of 100 to 250 ° C. A film containing an alicyclic structure-containing polymer resin having a glass transition temperature in such a range is excellent in durability without causing deformation or stress during use at high temperatures.

  The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the alicyclic structure-containing polymer resin used in the present invention is not particularly limited, but is usually 1.0 to 10.0, preferably 1.1. It is -4.0, More preferably, it is the range of 1.2-3.5.

  The alicyclic structure-containing polymer resin film can be obtained by molding a resin into a film shape. The method for molding the resin into a film is not particularly limited, and any known molding method, for example, a heat-melt molding method or a solution casting method can be adopted, but the volatile components in the sheet are reduced. From the viewpoint, it is preferable to use a heat-melt molding method.

  The hot melt molding method can be further classified into a melt extrusion molding method, a press molding method, an inflation method, an injection molding method, a blow molding method, a stretch molding method, and the like. Among these, in order to obtain a stretched film having excellent mechanical strength and thickness accuracy, it is preferable to use a melt extrusion molding method.

  The molding conditions are appropriately selected depending on the purpose of use and the molding method. In the case of the melt extrusion molding method, the cylinder temperature is suitably set in the range of preferably 100 to 600 ° C, more preferably 150 to 350 ° C.

  The thickness of the alicyclic structure-containing polymer tree resin film can be appropriately determined according to the purpose of use of the obtained stretched film. The thickness of the film is preferably 10 to 300 μm, more preferably 30 to 200 μm from the viewpoint of obtaining a uniform stretched film by a stable stretching process.

  Moreover, when manufacturing an alicyclic structure containing polymer resin film, another additive can be added in the range which does not inhibit the objective of this invention. Examples of other additives include plasticizers and deterioration inhibitors. The plasticizer is added to improve the mechanical properties of the film or to increase the drying speed. Examples of the plasticizer to be used include phosphoric acid esters and carboxylic acid esters.

  Examples of phosphate esters include triphenyl phosphate and tricresyl phosphate. Examples of carboxylic acid esters include phthalic acid esters such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate, and diphenyl phthalate; citrate esters such as triethyl O-acetylcitrate and tributyl O-acetylcitrate; butyl oleate Higher fatty acid esters such as methylacetyl ricinoleate and dibutyl sebacate; trimetic acid esters; and the like.

  Examples of the deterioration preventing agent include an antioxidant, a peroxide decomposing agent, a radical inhibitor, a metal deactivator, an acid scavenger, and amines. The deterioration preventing agents are described in JP-A-3-199201, JP-A-5-1907073, JP-A-5-194789, JP-A-5-271471, JP-A-6-107854, and the like. There is something.

  The addition amount of these other additives and other resins is usually 0 to 20% by weight, preferably 0 to 10% by weight, more preferably 0 to 5% by weight, based on the resin.

The alicyclic structure-containing polymer resin film obtained as described above is continuously stretched in an arbitrary angle direction with respect to the width direction, thereby having desired optical characteristics and with respect to the width direction of the film. Thus, a long stretched film having a slow axis (maximum refractive index direction) at an arbitrary angle can be obtained. That is, by arbitrarily setting the stretching direction, the refractive index in the in-plane slow axis direction, the refractive index in the direction perpendicular to the in-plane slow axis, and the refractive index in the thickness direction are set to desired values. Can be.
The retardation film thus obtained is a long stretched film, which can be rolled up, collected and stored. The long stretched film can be laminated with the polarizing plate (or polarizing film) produced in a long shape as it is long, and each is cut into a predetermined size, aligned and bonded. However, the occurrence of shaft misalignment can be reduced, which contributes to the improvement of productivity. In particular, by using a long polarizing film whose absorption axis is parallel to the longitudinal direction and a long stretched film (first retardation region) having a slow axis in a direction orthogonal to the longitudinal direction, or absorption By using a long polarizing film whose axis is perpendicular to the longitudinal direction and a long stretched film (first retardation region) having a slow axis in a direction parallel to the longitudinal direction, these films can be rolled-up. A long laminate is obtained by bonding with an adhesive or a pressure sensitive adhesive with a roll, and then the laminate is cut into a predetermined size and incorporated into a liquid crystal display device as a laminated polarizing plate. By performing the laminating process in a long state, it becomes easy to stack the polarizing film so that the angle between the absorption axis of the polarizing film and the slow axis of the first retardation region is orthogonal or parallel. As a result, extremely accurate bonding is possible, and productivity is improved.

[Second phase difference region]
In the present invention, the in-plane refractive indexes nx and ny in the second retardation region are preferably substantially equal, and the difference is preferably 0.05 or less, more preferably 0.02 or less. More preferably, it is 0.01 or less. Further, the second retardation region has an in-plane refractive index nx and ny (nx ≧ ny), a refractive index nz in the thickness direction, and a film thickness d, and Re = (nx−ny) × d. The defined in-plane retardation Re is preferably 100 nm or less, more preferably 50 nm or less, and further preferably 20 nm or less. Further, the more preferable range of the retardation Rth in the thickness direction defined by Rth = {(nx + ny) / 2−nz} × d varies depending on the optical characteristics of other optical members, and is particularly located closer. It varies greatly depending on the Rth of the protective film of the polarizing film (for example, triacetyl cellulose film). In order to effectively reduce light leakage in an oblique direction, it is −200 nm to −50 nm, more preferably −180 nm to −60 nm, and further preferably −160 nm to −70 nm.
The arrangement of the second retardation region in the slow axis direction is not particularly limited. However, in the case of exceeding 20 nm, in the configuration of FIG. 2, in the direction parallel to the transmission axis of the polarizing film arranged at a closer position. In the configuration of FIG. 3, it is preferable that the direction is perpendicular to the transmission axis of the polarizing film disposed at a closer position. With such arrangement, for example, the thickness of the first retardation region is reduced. Can be thin.

  As long as the second retardation region has the optical characteristics, the material and form thereof are not particularly limited. For example, both a retardation film made of a birefringent polymer film and a retardation film having a retardation layer formed by applying or transferring a low-molecular or high-molecular liquid crystalline compound on a transparent support are used. be able to. Moreover, each can also be laminated | stacked and used.

  A retardation film made of a birefringent polymer film having the above optical characteristics is a method in which a heat-shrinkable film is laminated and heated to apply a predetermined tension while stretching the polymer film in the thickness direction of the film (Japanese Patent Laid-Open No. 2000). -206328 and JP-A-2000-304925) and a method of applying a vinylcarbazole polymer and drying it (JP-A-2001-091746). In addition, as a retardation layer formed from a liquid crystalline compound having the above optical characteristics, a cholesteric discotic liquid crystal compound or composition containing a chiral structural unit is fixed after its helical axis is aligned substantially perpendicular to the substrate. Examples thereof include a layer formed by forming a rod-like liquid crystal compound or composition having a positive refractive index anisotropy and a composition formed by orienting the substrate substantially perpendicularly to the substrate and then immobilizing it (for example, JP-A-6-6 331826 and Japanese Patent No. 2853064). The rod-like liquid crystal compound may be a low molecular compound or a high molecular compound. Furthermore, not only one retardation layer but also a plurality of retardation layers can be laminated to form the second retardation region exhibiting the above optical characteristics. Further, the second retardation region may be configured so that the entire laminated body of the support and the retardation layer satisfies the optical characteristics. As the rod-like liquid crystal compound to be used, those that take a nematic liquid crystal phase, a smectic liquid crystal phase, and a lyotropic liquid crystal phase in a temperature range in which the orientation is fixed are preferably used. A liquid crystal exhibiting a smectic A phase and a B phase capable of obtaining uniform vertical alignment without fluctuation is preferable. These phases are preferable in that the birefringence is larger than that of the nematic liquid crystal phase and the thickness of the film can be reduced. In particular, in the presence of an additive, a rod-like liquid crystalline compound that becomes a liquid crystal state in an appropriate orientation temperature range is formed by using a composition containing the additive and the rod-like liquid crystalline compound. Is also preferable.

《Bar-shaped liquid crystalline compound》
The second retardation region may be formed from a composition containing a rod-like liquid crystal compound. Examples of the rod-like liquid crystalline compound include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines. , Phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles are preferably used. Not only the low-molecular liquid crystalline molecules as described above but also high-molecular liquid crystalline molecules can be used. As the liquid crystal molecules, those having a partial structure capable of causing polymerization or crosslinking reaction by actinic rays, electron beams, heat, or the like are preferably used. The number of the partial structures is 1 to 6, preferably 1 to 3.

  When the second retardation region includes a retardation layer formed by fixing the rod-like liquid crystalline compound in the aligned state, the rod-like liquid crystalline compound is substantially vertically aligned and fixed in that state. It is preferable to use a retardation layer. Substantially perpendicular means that the angle formed by the film surface and the director of the rod-like liquid crystal compound is in the range of 70 ° to 90 °. These liquid crystalline compounds may be aligned obliquely or may be changed so that the inclination angle gradually changes (hybrid alignment). Even in the case of oblique orientation or hybrid orientation, the average inclination angle is preferably 70 ° to 90 °, more preferably 80 ° to 90 °, and most preferably 85 ° to 90 °.

  The retardation layer formed from the rod-like liquid crystalline compound is formed on the support with a coating liquid containing the rod-like liquid crystalline compound and, if desired, the following polymerizable initiator, air interface vertical alignment agent and other additives. It can be formed by coating on the vertical alignment film formed, vertically aligning, and fixing the alignment state. When it is formed on a temporary support, it can also be produced by transferring the retardation layer onto the support. Furthermore, not only a single retardation layer but also a plurality of retardation layers can be laminated to form a second retardation region exhibiting the above optical characteristics. Further, the second retardation region may be configured so that the entire laminated body of the support and the retardation layer satisfies the optical characteristics.

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

  The vertically aligned liquid crystal compound is preferably fixed while maintaining the alignment state. The immobilization is preferably performed by a polymerization reaction of the polymerizable group (P) introduced into the liquid crystal compound. The polymerization reaction includes a thermal polymerization reaction using a thermal polymerization initiator and a photopolymerization reaction using a photopolymerization initiator. A photopolymerization reaction is preferred. Examples of the photopolymerization initiator include α-carbonyl compounds (described in US Pat. Nos. 2,367,661 and 2,367,670), acyloin ether (described in US Pat. No. 2,448,828), α-hydrocarbon substituted aromatic acyloin. Compound (described in US Pat. No. 2,722,512), polynuclear quinone compound (described in US Pat. Nos. 3,046,127 and 2,951,758), a combination of triarylimidazole dimer and p-aminophenyl ketone (US Pat. No. 3,549,367) Description), acridine and phenazine compounds (JP-A-60-105667, U.S. Pat. No. 4,239,850) and oxadiazole compounds (U.S. Pat. No. 4,212,970).

The amount of the photopolymerization initiator used is preferably 0.01 to 20% by mass, more preferably 0.5 to 5% by mass, based on the solid content of the coating solution. The light irradiation for polymerizing the rod-like liquid crystalline molecules preferably uses ultraviolet rays. The irradiation energy is preferably ^{20mJ / cm 2 ~50J / cm 2} , further preferably 100 to 800 mJ / cm ^2. In order to accelerate the photopolymerization reaction, light irradiation may be performed under heating conditions. The thickness of the first retardation region including the optically illegal layer is preferably 0.1 to 10 μm, more preferably 0.5 to 5 μm, and most preferably 1 to 5 μm.

<< Vertical alignment film >>
In order to align the liquid crystalline compound vertically on the alignment film side, it is important to reduce the surface energy of the alignment film. Specifically, the surface energy of the alignment film is lowered by the functional group of the polymer, thereby bringing the liquid crystalline compound into a standing state. As the functional group for reducing the surface energy of the alignment film, a hydrocarbon group having 10 or more fluorine atoms and carbon atoms is effective. In order to make a fluorine atom or a hydrocarbon group exist on the surface of the alignment film, it is preferable to introduce a fluorine atom or a hydrocarbon group into the side chain rather than the main chain of the polymer. The fluoropolymer preferably contains fluorine atoms in a proportion of 0.05 to 80% by mass, more preferably in a proportion of 0.1 to 70% by mass, and in a proportion of 0.5 to 65% by mass. More preferably, 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 cyclic, branched or linear. The aliphatic group is preferably an alkyl group (may be a cycloalkyl group) or an alkenyl group (may be a cycloalkenyl group). The hydrocarbon group may have a substituent that does not exhibit strong hydrophilicity, such as a halogen atom. The number of carbon atoms of the hydrocarbon group is preferably 10 to 100, more preferably 10 to 60, and most preferably 10 to 40. The main chain of the polymer preferably has a polyimide structure or a polyvinyl alcohol structure.

  Polyimide is generally synthesized by a condensation reaction of tetracarboxylic acid and diamine. A polyimide corresponding to a copolymer may be synthesized using two or more kinds of tetracarboxylic acids or two or more kinds of diamines. The fluorine atom or hydrocarbon group may be present in the repeating unit derived from tetracarboxylic acid, may be present in the repeating unit derived from diamine, or may be present in both repeating units. When introducing a hydrocarbon group into polyimide, it is particularly preferable to form a steroid structure in the main chain or 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 this specification, the steroid structure is a cyclopentanohydrophenanthrene ring structure or a ring structure in which a part of the ring bond is a double bond in the range of an aliphatic ring (a range that does not form an aromatic ring). means.

  Further, as a means for vertically aligning the liquid crystalline compound, a method of mixing an organic acid with a polymer of polyvinyl alcohol, modified polyvinyl alcohol, or polyimide can be suitably used. As the acid to be mixed, carboxylic acid, sulfonic acid and amino acid are preferably used. You may use what shows the acidity among the below-mentioned air interface aligning agent. Moreover, quaternary ammonium salts can also be used suitably. The mixing amount is preferably 0.1% by mass to 20% by mass and more preferably 0.5% by mass to 10% by mass with respect to the polymer.

  The saponification degree of the polyvinyl alcohol is preferably 70 to 100%, more preferably 80 to 100%. The polymerization degree of polyvinyl alcohol is preferably 100 to 5000.

  When aligning a rod-like liquid crystalline compound, the alignment film is preferably made of a polymer having a hydrophobic group as a functional group in the side chain. The specific type of functional group is determined according to the type of liquid crystal molecule and the required alignment state. For example, the modifying group of the modified polyvinyl alcohol can be introduced by copolymerization modification, chain transfer modification or block polymerization modification. Examples of modifying groups include hydrophilic groups (carboxylic acid groups, sulfonic acid groups, phosphonic acid groups, amino groups, ammonium groups, amide groups, thiol groups, etc.), hydrocarbon groups having 10 to 100 carbon atoms, fluorine atoms Substituted hydrocarbon groups, thioether groups, polymerizable groups (unsaturated polymerizable groups, epoxy groups, azirinidyl groups, etc.), alkoxysilyl groups (trialkoxy, dialkoxy, monoalkoxy) and the like can be mentioned. Specific examples of these modified polyvinyl alcohol compounds include, for example, paragraph numbers [0022] to [0145] in JP-A No. 2000-155216 and paragraph numbers [0018] to [0018] in JP-A No. 2002-62426. And the like described in [0022].

  The alignment film is formed by using a polymer having a side chain having a crosslinkable functional group bonded to the main chain or a polymer having a crosslinkable functional group on a side chain having a function of aligning liquid crystal molecules. When the retardation film is formed using a composition containing a polyfunctional monomer, the polymer in the alignment film and the polyfunctional monomer in the retardation film formed thereon can be copolymerized. As a result, a covalent bond is formed not only between the polyfunctional monomers but also between the alignment film polymers and between the polyfunctional monomer and the alignment film polymer, and the alignment film and the retardation film are firmly bonded. Therefore, the strength of the optical compensation sheet can be remarkably improved by forming the alignment film using a polymer having a crosslinkable functional group. The crosslinkable functional group of the alignment film polymer preferably contains a polymerizable group in the same manner as the polyfunctional monomer. Specific examples include those described in paragraphs [0080] to [0100] in JP-A-2000-155216.

  Apart from the crosslinkable functional group, the alignment film polymer can also be crosslinked using a crosslinking agent. Examples of the crosslinking agent include aldehydes, N-methylol compounds, dioxane derivatives, compounds that act by activating carboxyl groups, active vinyl compounds, active halogen compounds, isoxazole and dialdehyde starch. Two or more kinds of crosslinking agents may be used in combination. Specific examples include compounds described in paragraphs [0023] to [024] in JP-A-2002-62426. 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. The amount of the unreacted crosslinking agent remaining in the alignment film is preferably 1.0% by mass or less, and more preferably 0.5% by mass or less. By adjusting in this way, even if the alignment film is used for a long time in a liquid crystal display device or left in a high-temperature and high-humidity atmosphere for a long time, sufficient durability without occurrence of reticulation can be obtained.

  The alignment film can be basically formed by applying a composition containing the polymer and the crosslinking agent, which are alignment film forming materials, onto a transparent support, followed by drying by heating (crosslinking) and rubbing treatment. it can. As described above, the crosslinking reaction may be performed at an arbitrary time after coating on the transparent support. When a water-soluble polymer such as polyvinyl alcohol is used as the alignment film forming material, the coating solution is preferably a mixed solvent of an organic solvent (eg, methanol) having a defoaming action and water. The ratio of water: methanol is preferably 0: 100 to 99: 1, and more preferably 0: 100 to 91: 9. Thereby, generation | occurrence | production of a bubble is suppressed and the defect of the alignment film and also the phase difference layer surface reduces remarkably.

  The alignment film is preferably applied by spin coating, dip coating, curtain coating, extrusion coating, rod coating, or roll coating. A rod coating method is particularly preferable. The film thickness after drying is preferably 0.1 to 10 μm. Heating and drying can be performed at 20 ° C to 110 ° C. In order to form sufficient cross-linking, 60 ° C to 100 ° C is preferable, and 80 ° C to 100 ° C is particularly preferable. The drying time can be 1 minute to 36 hours, preferably 1 minute to 30 minutes. The pH is preferably set to an optimum value for the crosslinking agent to be used. When glutaraldehyde is used, the pH is 4.5 to 5.5, and 5 is particularly preferable.

  The alignment film is preferably provided on the transparent support. The alignment film is used by crosslinking the polymer layer as described above. The rubbing treatment is preferably not performed for the vertical alignment of the rod-like liquid crystalline compound. In addition, after aligning a liquid crystalline compound using an alignment film, the liquid crystalline compound is fixed in the alignment state to form a retardation layer, and only the retardation layer is formed on the polymer film (or transparent support). You may transcribe.

《Air interface vertical alignment agent》
Usually, since the liquid crystalline compound has a property of being inclined and aligned on the air interface side, it is necessary to control the alignment of the liquid crystalline compound vertically on the air interface side in order to obtain a uniformly vertically aligned state. . For this purpose, a phase difference film is formed by adding a compound that is unevenly distributed on the air interface side and that has the effect of vertically aligning the liquid crystalline compound by its excluded volume effect or electrostatic effect to the liquid crystal coating liquid. It is preferable to do this.

  As the air interface alignment agent, compounds described in JP-A Nos. 2002-20363 and 2002-129162 can be used. Also, paragraph numbers [0072] to [0075] of Japanese Patent Application No. 2002-212100, paragraph numbers [0037] to [0039] of Japanese Patent Application No. 2002-262239, paragraphs of Japanese Patent Application No. 2003-91752 Nos. [0071] to [0078], paragraph numbers [0052] to [0054], [0065] to [0066], [0092] to [0094] of Japanese Patent Application No. 2003-119959, Japanese Patent Application No. 2003-330303 The matters described in paragraph numbers [0028] to [0030] of the specification and paragraph numbers [0087] to [0090] of Japanese Patent Application No. 2004-003804 can also be appropriately applied to the present invention. Moreover, by mix | blending these compounds, applicability | paintability is improved and generation | occurrence | production of a nonuniformity or a repellency is suppressed.

  The amount of the air interface alignment agent used in the liquid crystal coating liquid is preferably 0.05% by mass to 5% by mass. Moreover, when using a fluorine-type air interface aligning agent, it is preferable that it is 1 mass% or less.

<Other materials in retardation layer>
Along with the liquid crystal compound, a plasticizer, a surfactant, a polymerizable monomer, and the like can be used in combination to improve the uniformity of the coating film, the strength of the film, the orientation of the liquid crystal compound, and the like. These materials are preferably compatible with the liquid crystal compound and do not inhibit the alignment.

  Examples of the polymerizable monomer include radically polymerizable or cationically polymerizable compounds. Preferably, it is a polyfunctional radically polymerizable monomer and is preferably copolymerizable with the above-described polymerizable group-containing liquid crystal compound. Examples thereof include those described in paragraph numbers [0018] to [0020] in JP-A No. 2002-296423. The amount of the compound added is generally in the range of 1 to 50% by mass and preferably in the range of 5 to 30% by mass with respect to the discotic liquid crystalline molecules.

  Examples of the surfactant include conventionally known compounds, and fluorine compounds are particularly preferable. Specifically, for example, compounds described in JP-A-2001-330725, paragraphs [0028] to [0056], and paragraphs [0069] to [0126] in Japanese Patent Application No. 2003-295212. And the compounds described.

  The polymer used together with the liquid crystal compound is preferably capable of thickening the coating solution. A cellulose ester can be mentioned as an example of a polymer. Preferable examples of the cellulose ester include those described in paragraph [0178] of JP-A No. 2000-155216. The addition amount of the polymer is preferably in the range of 0.1 to 10% by mass, and in the range of 0.1 to 8% by mass with respect to the liquid crystal molecules so as not to inhibit the alignment of the liquid crystal compound. It is more preferable.

[Support]
In the present invention, a retardation layer formed from a liquid crystal compound may be formed on a support. The support is preferably transparent, and specifically, the light transmittance is preferably 80% or more. The support preferably has a small wavelength dispersion. Specifically, the Re400 / Re700 ratio is preferably less than 1.2. Among these, a polymer film is preferable. The transparent support can also serve as the first retardation region, the second retardation region, or the polarizing plate protective film. The transparent support and the whole retardation layer may constitute the first retardation region or the second retardation region. The optical anisotropy of the support is preferably small, and the in-plane retardation (Re) is preferably 20 nm or less, more preferably 10 nm or less, and most preferably 5 nm or less.

  Examples of the polymer film as the support include cellulose ester, polycarbonate, polysulfone, polyethersulfone, polyacrylate and polymethacrylate films. A cellulose ester film is preferred, an acetylcellulose film is more preferred, and a triacetylcellulose film is most preferred. The polymer film is preferably formed by a solvent cast method. The thickness of the transparent support is preferably 20 to 500 μm, and more preferably 40 to 200 μm. In order to improve adhesion between the transparent support and the layer (adhesive layer, vertical alignment film or retardation layer) provided thereon, surface treatment (eg, glow discharge treatment, corona discharge treatment, ultraviolet light (UV) ) Treatment, flame treatment). An adhesive layer (undercoat layer) may be provided on the transparent support. Moreover, the average particle diameter is 10 to 100 nm in order to provide the transparent support or the long transparent support with slipperiness in the conveying process or to prevent the back surface and the surface from sticking after winding. It is preferable to use what formed the polymer layer which mixed the inorganic particle of about 5%-40% by solid content weight ratio by the application | coating or co-casting with the support body on the one side of the support body.

[Protective film for polarizing film]
As the protective film for the polarizing film, a protective film having no absorption in the visible light region, a light transmittance of 80% or more, and a retardation based on birefringence is preferable. Specifically, the in-plane Re is preferably 0 to 30 nm, more preferably 0 to 15 nm, and most preferably 0 to 5 nm. Further, the retardation Rth in the thickness direction of the protective film (for example, 7b and 19a in FIGS. 2 and 3) disposed on the liquid crystal cell side is preferably −50 nm to 40 nm, more preferably −30 nm to 35 nm. -20 nm to 20 nm is more preferable.

  The thickness of the protective film, particularly the thickness of the protective film arranged on the liquid crystal cell side is preferably 60 μm or less, more preferably 50 μm or less, and more preferably 40 μm or less from the viewpoint of reducing Rth. Is more preferable. However, when the protective film is composed of a plurality of layers in order to satisfy the above optical characteristics, the preferred range of thickness is not limited to this range.

Any film having this characteristic can be used preferably, but from the viewpoint of the durability of the polarizing film, it is more preferable to contain a cellulose acylate or norbornene-based film.
As the norbornene-based polymer, norbornene and its derivatives, tetracyclododecene and its derivatives, dicyclopentadiene and its derivatives, methanotetrahydrofluorene and its monomers as a main component of a norbornene-based monomer polymer, Ring-opening polymer of norbornene monomer, ring-opening copolymer of norbornene monomer and other monomer capable of ring-opening copolymerization, addition polymer of norbornene monomer, copolymerizable with norbornene monomer Examples include addition copolymers with other monomers and hydrogenated products thereof. Among these, from the viewpoints of heat resistance, mechanical strength, and the like, a ring-opening polymer hydride of a norbornene monomer is most preferable. The molecular weight of the norbornene-based polymer, the monocyclic olefin polymer, or the cyclic conjugated diene polymer is appropriately selected depending on the purpose of use, but is a cyclohexane solution (a toluene solution if the polymer resin does not dissolve). The polyisoprene or polystyrene-converted weight average molecular weight measured by gel permeation chromatography is usually 5,000 to 500,000, preferably 8,000 to 200,000, more preferably 10,000 to 100,000. When the thickness is within the range, the mechanical strength of the film (A) and the moldability are highly balanced and suitable.

  The cellulose acylate is not particularly limited, and the acyl group may be an aliphatic group or an allyl group. They are, for example, alkyl carbonyl esters, alkenyl carbonyl esters, aromatic carbonyl esters, aromatic alkyl carbonyl esters, etc. of cellulose, each of which may further have a substituted group, and an ester having a total carbon number of 22 or less. Groups are preferred. These preferred cellulose acylates include acyl groups having a total carbon number of 22 or less in the ester moiety (for example, acetyl, propionyl, butyroyl, barrel, heptanoyl, octanoyl, decanoyl, dodecanoyl, tridecanoyl, hexadecanoyl, octadecanoyl, etc. ), Arylcarbonyl groups (acrylic, methacrylic, etc.), allylcarbonylkis (benzoyl, naphthaloyl etc.) and cinnamoyl groups. Among these, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate stearate, cellulose acetate benzoate, etc. are not particularly limited in the case of mixed esters, but preferably acetate is the total ester. It is preferable that it is 30 mol% or more.

  Among these, cellulose acylate is preferred, and photographic grades are particularly preferred, and commercially available photographic grades can be obtained with satisfactory quality such as viscosity average degree of polymerization and substitution degree. Manufacturers of photographic grade cellulose triacetate include Daicel Chemical Industries, Ltd. (for example, LT-20, 30, 40, 50, 70, 35, 55, 105, etc.), Eastman Kodak Company (for example, CAB-551). 0.01, CAB-551-0.02, CAB-500-5, CAB-381-0.5, CAB-381-02, CAB-381-20, CAB-321-0.2, CAP-504 0.2, CAP-482-20, CA-398-3, etc.), Coatles, Hoechst, etc., any of which can use photographic grade cellulose acylate. In addition, a plasticizer, a surfactant, a retardation modifier, a UV absorber, and the like can be mixed for the purpose of controlling the mechanical properties and optical properties of the film (reference material: Japanese Patent Application Laid-Open No. 2002-277632). Gazette, JP-A-2002-182215)

As a method of forming the transparent resin into a sheet or film, for example, either a hot melt molding method or a solution casting method can be used. The heat-melt molding method can be further classified into an extrusion molding method, a press molding method, an inflation molding method, an injection molding method, a blow molding method, a stretch molding method, etc. Among these methods, mechanical strength, surface In order to obtain a film excellent in accuracy and the like, the extrusion molding method, the inflation molding method, and the press molding method are preferable, and the extrusion molding method is most preferable. The molding conditions are appropriately selected depending on the purpose of use and the molding method. In the case of the heat-melt molding method, the cylinder temperature is preferably set in the range of preferably 100 to 400 ° C, more preferably 150 to 350 ° C. The thickness of the sheet or film is preferably 10 to 300 μm, more preferably 30 to 200 μm.
When the glass transition temperature of the transparent resin is defined as Tg, the stretching of the sheet or film is preferably in a temperature range of Tg-30 ° C to Tg + 60 ° C, more preferably in a temperature range of Tg-10 ° C to Tg + 50 ° C. In at least one direction, the stretching ratio is preferably 1.01 to 2 times. The stretching direction may be at least one direction, but when the sheet is obtained by extrusion, the direction is preferably the mechanical flow direction (extrusion direction) of the resin. A free shrink uniaxial stretching method, a fixed width uniaxial stretching method, a biaxial stretching method, and the like are preferable. The optical characteristics can be controlled by controlling the draw ratio and the heating temperature.

  As a method for reducing the Rth of a cellulose acylate film, it is effective to mix a compound having a non-planar structure into the film. Moreover, the method of Unexamined-Japanese-Patent No. 11-246704, Unexamined-Japanese-Patent No. 2001-247717, Japanese Patent Application No. 2003-379975, etc. are mentioned. Rth can also be reduced by reducing the thickness of the cellulose acylate film.

  A polarizing plate protective film having negative optical characteristics for Rth can be obtained by a method of stretching a polymer film in the thickness direction of the film (e.g., Japanese Patent Application Laid-Open No. 2000-162436) or by applying a vinylcarbazole polymer and drying it. It can be easily formed by a method (eg, Japanese Patent Application Laid-Open No. 2001-091746). In addition, the protective film may contain a liquid crystal material, and for example, may contain a retardation layer formed from a liquid crystalline compound having a negative optical characteristic for Rth. The retardation layer is a layer formed by fixing a cholesteric discotic liquid crystal compound or composition containing a chiral structural unit with its helical axis aligned substantially perpendicular to the substrate, and having a positive refractive index anisotropy. Examples thereof include a layer formed by orienting the rod-like liquid crystal compound or composition of the present invention on the substrate and then fixing it to the substrate (see, for example, JP-A-6-331826 and Japanese Patent No. 2853064). The rod-like liquid crystal compound may be a low molecular compound or a high molecular compound. Furthermore, it is possible to form a protective film that exhibits not only one retardation layer but also a plurality of retardation layers to exhibit optical characteristics with negative Rth. Further, the protective layer may be configured so that the entire laminate of the support and the retardation layer satisfies a negative optical characteristic of Rth. As the rod-like liquid crystal compound to be used, those that take a nematic liquid crystal phase, a smectic liquid crystal phase, and a lyotropic liquid crystal phase in a temperature range in which the orientation is fixed are preferably used. A liquid crystal exhibiting a smectic A phase and a B phase capable of obtaining uniform vertical alignment without fluctuation is preferable. In particular, in the presence of an additive, a rod-like liquid crystalline compound that becomes a liquid crystal state in an appropriate orientation temperature range is formed by using a composition containing the additive and the rod-like liquid crystalline compound. Is also preferable.

  In order to improve the adhesion between the protective film and the layer (adhesive layer, alignment film or retardation layer) provided thereon, the film is subjected to surface treatment (eg, glow discharge treatment, corona discharge treatment, ultraviolet (UV) treatment, flame) Processing) may be performed. An adhesive layer (undercoat layer) may be provided on the transparent support. Moreover, the average particle diameter is 10 to 100 nm in order to provide the transparent support or the long transparent support with slipperiness in the conveying process or to prevent the back surface and the surface from sticking after winding. It is preferable to use what formed the polymer layer which mixed the inorganic particle of about 5%-40% by solid content weight ratio by the application | coating or co-casting with the support body on the one side of the support body.

  The features of the present invention will be described more specifically with reference to examples and comparative examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

<Preparation of IPS mode liquid crystal cell 1>
As shown in FIG. 1, electrodes (2 and 3 in FIG. 1) are arranged on one glass substrate so that the distance between adjacent electrodes is 20 μm, and a polyimide film is used as an alignment film on it. A rubbing process was performed. The rubbing process was performed in the direction 4 shown in FIG. A polyimide film was provided on one surface of a separately prepared glass substrate, and a rubbing treatment was performed to obtain an alignment film. The two glass substrates are stacked and bonded so that the alignment films face each other, the distance between the substrates (gap; d) is 3.9 μm, and the rubbing direction of the two glass substrates is antiparallel. Next, a nematic liquid crystal composition having a refractive index anisotropy (Δn) of 0.0769 and a dielectric anisotropy (Δε) of 4.5 was enclosed. The value of d · Δn of the liquid crystal layer was 300 nm.

<Preparation of the first retardation region 1, the first retardation region 2, the first retardation region 3, the first retardation region 4, and the first retardation region 5>
A polymer film forming the first retardation region was produced as follows.
A norbornene-based film (Zeonor, manufactured by Nippon Zeon Co., Ltd.) having a thickness of 100 μm was uniaxially stretched (temperature 180 ° C., continuously stretched) to obtain the following five types of stretched birefringence roll films.

The optical characteristics were calculated by measuring the light incident angle dependency of Re using an automatic birefringence meter (KOBRA-21ADH, manufactured by Oji Scientific Instruments).
First retardation region 1; Re 80 nm, Rth 80 nm, Nz 1.2
First retardation region 2; Re 140 nm, Rth 70 nm, Nz 1.0
First retardation region 3; Re 80 nm, Rth 80 nm, Nz 1.5
First retardation region 4; Re 170 nm, Rth 85 nm, Nz 1.0
First retardation region 5; Re140 nm, Rth70 nm, Nz1.0
The first retardation regions 1 to 3 were subjected to lateral uniaxial stretching, and the slow axis direction was orthogonal to the longitudinal direction of the roll film. The first retardation regions 4 and 5 were subjected to longitudinal uniaxial stretching, and the slow axis direction was parallel to the longitudinal direction of the roll film.

<Preparation of Second Phase Difference Region 1, Second Phase Difference Region 2, Second Phase Difference Region 3, and Second Phase Difference Region 4>
A commercially available cellulose acetate film (Fujitac TD80UF, manufactured by Fuji Photo Film Co., Ltd., Re = 2 nm, Rth = 48 nm), and a commercially available vertical alignment film on the first retardation regions 1 to 5 subjected to corona discharge treatment ( JALS-204R (manufactured by Nippon Synthetic Rubber Co., Ltd.) was diluted 1: 1 with methyl ethyl ketone, and then continuously applied with a wire bar coater (application amount 2.4 ml / m ² ). Immediately, it was dried with warm air of 120 ° C. for 120 seconds.

  Next, 3.8 g of the following rod-like liquid crystal compound, 0.06 g of photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy), 0.02 g of sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.), A solution in which 0.002 g of the air interface side vertical alignment agent was dissolved in 9.2 g of methyl ethyl ketone was prepared. This solution was continuously applied to the alignment film side of the film on which the alignment film was formed with a wire bar having the following count, and heated at 100 ° C. for 2 minutes to align the rod-like liquid crystal compound. Next, the rod-shaped liquid crystal compound was crosslinked by UV irradiation for 20 seconds with a 120 W / cm high-pressure mercury lamp at 80 ° C., and then allowed to cool to room temperature to prepare a roll-like retardation layer.

────────────────────────────────────
Film name Retardation layer made of rod-shaped liquid crystal Support Wire bar count
Second phase difference area name ─────────────────────────────────────
Film A Second retardation region 1 First retardation region 1 # 1.5
Film B Second retardation region 2 First retardation region 2 # 2.0
Film C Second retardation region 3 First retardation region 3 # 3.0
Film D Second phase difference region 4 First phase difference region 4 # 2.7
Film E Second retardation region 2 First retardation region 5 # 2.0
────────────────────────────────────
Using an automatic birefringence meter (KOBRA-21ADH, manufactured by Oji Scientific Instruments Co., Ltd.), measure the light incident angle dependency of Re of the manufactured film, and subtract the contribution of the support measured in advance. And calculating the optical characteristics of only the second phase difference region,
In the second phase difference region 1, Re is 0 nm, Rth is −75 nm,
In the second retardation region 2, Re is 0 nm, Rth is −100 nm,
In the second phase difference region 3, Re is 0 nm, Rth is −150 nm,
In the second phase difference region 4, Re is 0 nm and Rth is -135 nm.
In either case, it was confirmed that the rod-like liquid crystals were aligned substantially vertically.

<Production of Polarizing Plate Protective Film 1>
(Polarizing plate protective film 1)
The following composition was put into a mixing tank, stirred while heating to dissolve each component, and a cellulose acetate solution A was prepared.
<Composition of cellulose acetate solution A>
Cellulose acetate having a substitution degree of 2.86 100 parts by weight Triphenyl phosphate (plasticizer) 7.8 parts by weight Biphenyl diphenyl phosphate (plasticizer) 3.9 parts by weight Methylene chloride (first solvent) 300 parts by weight Methanol (second solvent) ) 54 parts by mass 1-butanol 11 parts by mass

The following composition was charged into another mixing tank, stirred while heating to dissolve each component, and an additive solution B-1 was prepared.
<Additive solution B-1 composition>
Methylene chloride 80 parts by weight Methanol 20 parts by weight The following optical anisotropy reducing agent 40 parts by weight

40 parts by mass of the additive solution B-1 was added to 477 parts by mass of the cellulose acetate solution A, and the dope was prepared by sufficiently stirring. The dope was cast from a casting port onto a drum cooled to 0 ° C. The solvent content is peeled off at 70% by mass, both ends in the width direction of the film are fixed with a pin tenter (the pin tenter described in FIG. 3 of JP-A-4-1009), and the solvent content is 3-5% by mass. In this state, the film was dried while maintaining an interval at which the stretching ratio in the transverse direction (direction perpendicular to the machine direction) was 3%. Then, it further dried by conveying between the rolls of the heat processing apparatus, and produced the polarizing plate protective film 1 with a thickness of 80 μm.
Using an automatic birefringence meter (KOBRA-21ADH, manufactured by Oji Scientific Instruments Co., Ltd.), the light incident angle dependence of Re was measured, and the optical characteristics were calculated. Re was 1 nm and Rth was 6 nm. I was able to confirm.

<Preparation of polarizing plate A>
Next, iodine is adsorbed to the stretched polyvinyl alcohol film to produce a polarizing film, and saponification is performed on a commercially available cellulose acetate film (Fujitac TD80UF, manufactured by Fuji Photo Film Co., Ltd., Re = 2 nm, Rth = 48 nm). Using a polyvinyl alcohol-based adhesive, it was attached to one side of the polarizing film. In the same manner, a commercially available cellulose acetate film (Fujitac T40UZ, manufactured by Fuji Photo Film Co., Ltd., Re = 1 nm, Rth = 35 nm, thickness 40 μm) was subjected to saponification treatment, and a polarizing film was formed using a polyvinyl alcohol-based adhesive. Affixed to the other side to form polarizing plate A.

<Preparation of polarizing plate B>
A polarizing film was produced in the same manner, and a commercially available cellulose acetate film (Fujitac TD80UF, manufactured by Fuji Photo Film Co., Ltd.) was subjected to saponification treatment and attached to one side of the polarizing film using a polyvinyl alcohol-based adhesive. . In the same manner, the polarizing plate protective film 1 manufactured as described above was attached to the other side of the polarizing film to form a polarizing plate B.

<Preparation of polarizing plate C>
In the same manner, a polarizing film is produced, and a commercially available cellulose acetate film (Fujitac TD80UF, manufactured by Fuji Photo Film Co., Ltd.) is saponified, and is attached to both surfaces of the polarizing film using a polyvinyl alcohol adhesive. Plate C was formed.

[Example 1]
Acrylic adhesive is used on the polarizing plate protective film T40UZ side of the polarizing plate A so that the produced roll film A has the first retardation region 1 side on the polarizing film side and the transmission axis of the polarizing film and the first Bonding was continued so that the slow axis of the phase difference region 1 was parallel.
After the laminated body of the polarizing plate A and the film A is cut into a predetermined size, the laminate is parallel to the rubbing direction of the liquid crystal cell on one side of the IPS mode liquid crystal cell 1 produced above. (That is, the slow axis of the first retardation region 1 is parallel to the slow axis of the liquid crystal molecules of the liquid crystal cell during black display) and the second retardation region 1 surface side is liquid crystal Affixed to the cell side.
Subsequently, another polarizing plate A is placed on the other side of the IPS mode liquid crystal cell 1 so that the Fujitac T40UZ side is the liquid crystal cell side, and the polarizing plate A with the retardation region previously bonded is crossed Nicol. The liquid crystal display device was manufactured by pasting so as to be arranged. The leakage light of the liquid crystal display device thus manufactured was measured. The leaked light when observed from the left oblique direction of 60 ° was 0.10%.

[Example 2]
Using an acrylic adhesive on the polarizing plate protective film 1 side of the polarizing plate B, the produced roll-shaped film B is arranged such that the first retardation region 2 side is the polarizing film side and the transmission axis of the polarizing film and the first Bonding was continuously performed so that the slow axis of the phase difference region 2 was parallel.
After the laminated body of the polarizing plate B and the film B is cut into a predetermined size, the transmission body of the polarizing plate is parallel to the rubbing direction of the liquid crystal cell on one of the IPS mode liquid crystal cells 1 produced above. (That is, the slow axis of the first retardation region 2 is parallel to the slow axis of the liquid crystal molecules of the liquid crystal cell during black display), and the second retardation region 2 surface side is liquid crystal Affixed to the cell side.
Subsequently, another polarizing plate B is attached to the other side of the IPS mode liquid crystal cell 1 so that the polarizing plate protective film 1 side is on the liquid crystal cell side, and the polarizing plate B with a retardation region bonded first. A liquid crystal display device was manufactured by pasting in a crossed Nicol arrangement. The leakage light of the liquid crystal display device thus manufactured was measured. The leakage light when observed from the left oblique direction of 60 ° was 0.05%.

[Example 3]
Using an acrylic adhesive for the polarizing plate C, the roll film C thus prepared is such that the first retardation region 3 side is the polarizing film side, and the transmission axis of the polarizing film and the retardation phase of the first retardation region 3 are They were laminated together so that the axes were parallel.
After the laminated body of the polarizing plate C and the film C is cut into a predetermined size, this is applied to one of the IPS mode liquid crystal cells 1 produced above, and the transmission axis of the polarizing plate is parallel to the rubbing direction of the liquid crystal cell. (That is, the slow axis of the first retardation region 3 is parallel to the slow axis of the liquid crystal molecules of the liquid crystal cell during black display), and the second retardation region 3 surface side is liquid crystal. Affixed to the cell side.
Subsequently, the polarizing plate B is placed on the other side of the IPS mode liquid crystal cell 1 so that the polarizing plate protective film 1 side is on the liquid crystal cell side, and the polarizing plate with retardation region C is placed in a crossed Nicols arrangement. A liquid crystal display device was manufactured. The leakage light of the liquid crystal display device thus manufactured was measured. The leakage light when observed from the left oblique direction of 60 ° was 0.05%.

[Example 4]
Using an acrylic adhesive on the polarizing plate protective film T40UZ side of the polarizing plate A, the produced roll film D is aligned with the transmission axis of the polarizing film so that the second retardation region 4 side is on the polarizing film side. Bonding was continuously performed so that the slow axis of one phase difference region 4 was orthogonal.
After the laminated body of the polarizing plate A and the film D is cut into a predetermined size, the transmission body of the polarizing plate is parallel to the rubbing direction of the liquid crystal cell on one side of the IPS mode liquid crystal cell 1 produced above. (That is, the slow axis of the first retardation region 4 is perpendicular to the slow axis of the liquid crystal molecules of the liquid crystal cell during black display), and the first retardation region 4 surface side is liquid crystal. Affixed to the cell side.
Subsequently, another polarizing plate A is placed on the other side of the IPS mode liquid crystal cell 1 so that the Fujitac T40UZ side is the liquid crystal cell side, and the polarizing plate A with the retardation region previously bonded is crossed Nicol. The liquid crystal display device was manufactured by pasting so as to be arranged. The leakage light of the liquid crystal display device thus manufactured was measured. The leakage light when observed from the left oblique direction of 60 ° was 0.11%.

[Example 5]
Using the acrylic adhesive on the polarizing plate protective film 1 side of the polarizing plate B, the produced roll-shaped film E is arranged so that the second retardation region 2 side is the polarizing film side and the transmission axis of the polarizing film and the first Bonding was continued so that the slow axis of the phase difference region 5 would be orthogonal.
After the laminated body of the polarizing plate B and the film E is cut into a predetermined size, the transmission axis of the polarizing plate is parallel to the rubbing direction of the liquid crystal cell on one of the IPS mode liquid crystal cells 1 produced above. (That is, the slow axis of the first retardation region 5 is orthogonal to the slow axis of the liquid crystal molecules of the liquid crystal cell during black display), and the first retardation region 5 surface side is liquid crystal Affixed to the cell side.
Subsequently, another polarizing plate B is attached to the other side of the IPS mode liquid crystal cell 1 so that the polarizing plate protective film 1 side is on the liquid crystal cell side, and the polarizing plate B with a retardation region bonded first. A liquid crystal display device was manufactured by pasting in a crossed Nicol arrangement. The leakage light of the liquid crystal display device thus manufactured was measured. The leakage light when observed from the left oblique direction of 60 ° was 0.05%.

[Example 6]
<Preparation of Ferroelectric Liquid Crystal Cell 1>
A polyimide film on an ITO electrode glass substrate was provided as an alignment film, and a rubbing treatment was performed. Two substrates are manufactured, the alignment films are made to face each other, the distance between the substrates (gap; d) is set to 1.9 μm, and the rubbing directions of the two glass substrates are parallel to each other and bonded together. Next, a ferroelectric liquid crystal composition having a refractive index anisotropy (Δn) of 0.15 and a spontaneous polarization (Ps) of 12 nCcm −2 was sealed. The value of d · Δn of the liquid crystal layer was 280 nm.

Using an acrylic adhesive on the polarizing plate protective film 1 side of the polarizing plate B, the produced roll-shaped film B is arranged such that the first retardation region 2 side is the polarizing film side and the transmission axis of the polarizing film and the first Bonding was continuously performed so that the slow axis of the phase difference region 2 was parallel.
After the laminated body of the polarizing plate B and the film B is cut into a predetermined size, this is divided into one of the ferroelectric liquid crystal cell 1 and the slow axis of the first retardation region 2 is formed in the liquid crystal cell. Affixing was performed so that the slow axis of the liquid crystal molecules when a DC voltage of 10 V was applied was parallel to the liquid crystal cell side. Subsequently, another polarizing plate B is attached to the other side of the IPS mode liquid crystal cell 1 so that the polarizing plate protective film 1 side is on the liquid crystal cell side, and the polarizing plate B with a retardation region bonded first. A liquid crystal display device was manufactured by pasting in a crossed Nicol arrangement. The leakage light of the liquid crystal display device thus manufactured was measured. The leakage light when observed from the left oblique direction of 60 ° was 0.05%.

[Example 7]
Using an acrylic adhesive on the polarizing plate protective film 1 side of the polarizing plate B, the film E cut into a sheet shape is arranged such that the first retardation region 5 side is the polarizing film side and the transmission axis of the polarizing film is Bonding was performed so that the slow axis of one phase difference region 5 was parallel.
After the laminated body of the polarizing plate B and the film E is cut into a predetermined size, the transmission axis of the polarizing plate is parallel to the rubbing direction of the liquid crystal cell on one of the IPS mode liquid crystal cells 1 produced above. (That is, the slow axis of the first retardation region 5 is orthogonal to the slow axis of the liquid crystal molecules of the liquid crystal cell during black display), and the first retardation region 5 surface side is liquid crystal Affixed to the cell side.
Subsequently, another polarizing plate B is bonded to the other side of the IPS mode liquid crystal cell 1 so that the polarizing plate protective film 1 side is on the liquid crystal cell side, and the polarizing plate B with a retardation region previously bonded. A liquid crystal display device was manufactured by pasting in a crossed Nicol arrangement. The leakage light of the liquid crystal display device thus manufactured was measured. The leakage light when observed from the left oblique direction of 60 ° was 0.18%.

[Example 8]
Using an acrylic adhesive on the polarizing plate protective film 1 side of the polarizing plate B, the film B cut into a sheet shape is arranged such that the second retardation region 2 side is the polarizing film side and the transmission axis of the polarizing film is Bonding was performed so that the slow axis of one phase difference region 2 was orthogonal.
After the laminated body of the polarizing plate B and the film B is cut into a predetermined size, the transmission body of the polarizing plate is parallel to the rubbing direction of the liquid crystal cell on one of the IPS mode liquid crystal cells 1 produced above. (That is, the slow axis of the first retardation region 2 is perpendicular to the slow axis of the liquid crystal molecules of the liquid crystal cell during black display), and the first retardation region 2 surface side is liquid crystal Affixed to the cell side.
Subsequently, another polarizing plate B is attached to the other side of the IPS mode liquid crystal cell 1 so that the polarizing plate protective film 1 side is on the liquid crystal cell side, and the polarizing plate B with a retardation region bonded first. A liquid crystal display device was manufactured by pasting in a crossed Nicol arrangement. The leakage light of the liquid crystal display device thus manufactured was measured. The leakage light when observed from the left oblique direction of 60 ° was 0.20%.

[Comparative Example 1]
A commercially available polarizing plate (HLC2-5618, manufactured by Sanritz Co., Ltd.) was attached to both sides of the produced IPS mode liquid crystal cell 1 in a crossed Nicol arrangement to produce a liquid crystal display device. An optical compensation film was not used. In the liquid crystal display device, as in Example 1, the polarizing plate was attached so that the transmission axis of the upper polarizing plate was parallel to the rubbing direction of the liquid crystal cell. The leakage light of the liquid crystal display device thus manufactured without the retardation region of the present invention was measured. Light leakage when observed from the left oblique direction of 60 ° was 0.55%.

It is the schematic which shows the pixel area example of the liquid crystal display device of this invention. It is the schematic which shows an example of the liquid crystal display device of this invention. It is the schematic which shows the other example of the liquid crystal display device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal element pixel area 2 Pixel electrode 3 Display electrode 4 Rubbing direction 5a, 5b Director of liquid crystal compound at the time of black display 6a, 6b Director of liquid crystal compound at the time of white display 7a, 7b, 19a, 19b Protective film for polarizing film 8, 20 Polarizing film 9, 21 Polarizing transmission axis 10 of polarizing film First retardation region 11 Slow axis 12 of first retardation region Second retardation region 13, 17 Cell substrate 14, 18 Cell substrate rubbing direction 15 Liquid crystal Layer 16 Slow axis direction of liquid crystal layer

Claims (9)

The liquid crystal cell includes at least a first polarizing film, a first retardation region, a second retardation region, a liquid crystal cell having a liquid crystal layer sandwiched between a pair of substrates, and a second polarizing film. A liquid crystal display device in which liquid crystal molecules are aligned parallel to the surfaces of the pair of substrates,
Using the in-plane refractive indices nx and ny (nx ≧ ny), the refractive index nz in the thickness direction, and the thickness d of the film, the first retardation region defined by Re = (nx−ny) × d Retardation Re is 60 nm to 200 nm,
The value Nz of the first phase difference region defined by Nz = (nx−nz) / (nx−ny) exceeds 0.8 and is 1.5 or less.
The first retardation region has a retardation layer obtained by stretching an alicyclic structure-containing polymer resin film,
In-plane refractive indices nx and ny are substantially equal, nx <nz, and the thickness of the second retardation region defined by Rth = {(nx + ny) / 2−nz} × d. A liquid crystal display device in which the direction retardation Rth is -200 nm to -50 nm and the transmission axis of the first polarizing film is parallel to the slow axis direction of the liquid crystal molecules during black display. The first polarizing film, the first retardation region, the second retardation region, and the liquid crystal cell are arranged in this order, and the slow axis of the first retardation region is substantially the transmission axis of the first polarizing film. The liquid crystal display device according to claim 1, which is parallel. The first polarizing film, the second retardation region, the first retardation region, and the liquid crystal cell are arranged in this order, and the slow axis of the first retardation region is substantially orthogonal to the transmission axis of the first polarizing film. The liquid crystal display device according to claim 1. The liquid crystal display device according to claim 1, wherein the retardation layer of the first retardation region is formed by cutting a long stretched film obtained by stretching a norbornene-based film. A pair of protective films disposed between at least one of the first polarizing film and the second polarizing film, and a thickness direction retardation Rth of the protective film on the side closer to the liquid crystal layer of the pair of protective films. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is 40 nm to −50 nm. A pair of protective films disposed between at least one of the first polarizing film and the second polarizing film, and a thickness direction retardation Rth of the protective film on the side closer to the liquid crystal layer of the pair of protective films. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is 20 nm to −20 nm. A pair of protective films disposed between at least one of the first polarizing film and the second polarizing film, and the thickness of the protective film on the side close to the liquid crystal layer of the pair of protective films is 60 μm or less. Item 7. The liquid crystal display device according to any one of items 1 to 6. The ratio Re (450) / Re (750) of the retardation Re (450) and the in-plane retardation Re (750) with a wavelength of 750 nm in the in-plane letter with a wavelength of 450 nm of the retardation layer of the first retardation region is 1. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is less than .1.   A pair of protective films disposed between the first polarizing film and the second polarizing film, wherein at least the protective film on the side close to the liquid crystal layer includes a cellulose acylate film or a norbornene-based film; The liquid crystal display device according to claim 1.

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