JP2009036839A - Liquid crystal panel and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal panel equipped with a combination type polarizing plate which is formed so as to have a large area and which contributes to improvement of a viewing angle, and also to provide a liquid crystal display device. <P>SOLUTION: The liquid crystal panel 100 is equipped with: a liquid crystal cell 9; a first optical lamination body A which is provided with one polarizing plate disposed on one surface side of the liquid crystal cell, and an optical compensation layer 37 which is disposed between the liquid crystal cell and the one polarizing plate, and the index ellipsoid of which satisfies inequality nx>ny>nz; and a second optical lamination body B which is provided with the other polarizing plate disposed on the other surface side of the liquid crystal cell, and an optical compensation layer 38 which is disposed between the liquid crystal cell and the other polarizing plate, and the index ellipsoid of which satisfies inequality nx>ny>nz. At least one of the first and the second optical lamination bodies is the combination type polarizing plate having a first polarizing plate 1 and a second polarizing plate 2 arranged on the surface of the optical compensation layer opposite the liquid crystal cell side-by-side in such a way that at least a set of end faces are opposite each other. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid crystal cell and a liquid crystal display device including a combination type polarizing plate in which a plurality of polarizing plates are arranged in parallel on an optical compensation layer in a state where end faces are opposed to each other.

  Liquid crystal display devices are used in various applications such as mobile phones, monitors, televisions, signboards, and blackboards. In recent years, for example, liquid crystal display devices for television and billboard use have rapidly increased in screen size, and 65-inch size liquid crystal devices have been put into practical use. Under such market trends, there is an urgent need to increase the size of optical films used in liquid crystal display devices.

  As a main optical film used for a liquid crystal display device, there are a polarizing plate that transmits linearly polarized light, a birefringent film (also referred to as a retardation film, an optical compensation film, or the like) having a predetermined retardation. The polarizing plate includes a polarizer (also referred to as a polarizing film or a polarizing element) and is usually disposed on each side of the liquid crystal cell. The birefringent film is usually disposed between the polarizer and the liquid crystal cell, and contributes to improving the viewing angle of the liquid crystal display device.

By the way, as the polarizer of the polarizing plate, a dyed stretched film produced by dyeing a long polyvinyl alcohol film with a dichroic substance and uniaxially stretching in the longitudinal direction is usually used. This dyed stretched film is generally considered to obtain a polarizer having excellent polarization characteristics as the stretch ratio is increased. In fact, a polarizer having a high degree of polarization has been proposed by performing predetermined stretching. (For example, refer to Patent Document 1).
JP 2004-341515 A

  However, in order to obtain a polarizer having excellent polarization characteristics, if the stretch ratio is increased, the effective width of the dyed stretched film becomes narrow due to necking. Since the maximum dimension of the polarizer formed from the dyed stretched film is regulated by the effective width of the dyed stretched film, it is difficult to obtain a large-area polarizing plate corresponding to the increase in size of the liquid crystal display device. In addition, even when the draw ratio is relatively low, the maximum size of the polarizer is regulated by the size of the dyed stretched film in the TD direction, and there is a limit to increasing the size of the production facility for the dyed stretched film, Similarly, it is difficult to obtain a large-area polarizing plate.

  Accordingly, an object of the present invention is to provide a liquid crystal panel and a liquid crystal display device including a combination polarizing plate that can be formed in a large area and can contribute to an improvement in viewing angle.

  The liquid crystal panel according to the present invention includes a liquid crystal cell, one polarizing plate disposed on one surface side of the liquid crystal cell, and a refractive index ellipse disposed between the liquid crystal cell and the one polarizing plate. A first optical laminate including an optical compensation layer satisfying a relationship of nx> ny> nz, the other polarizing plate disposed on the other surface side of the liquid crystal cell, and the liquid crystal cell A second optical laminate including an optical compensation layer disposed between the polarizing plate and a refractive index ellipsoid satisfying a relationship of nx> ny> nz, and the first optical laminate, At least one of the second optical laminates includes a first polarizing plate and a second polarizing plate arranged side by side on a surface opposite to the liquid crystal cell of the optical compensation layer so that at least one pair of end faces face each other. It is a combination-type polarizing plate having the polarizing plate.

  The combination polarizing plate included in the liquid crystal panel according to the present invention includes the first polarizing plate and the second polarizing plate such that at least one pair of end surfaces of the end surface of the first polarizing plate and the end surface of the second polarizing plate face each other. Are arranged in parallel on one surface of the optical compensation layer. Therefore, even if the first polarizing plate and the second polarizing plate themselves cannot be formed in a large area due to the size restriction of the polarizer, the first polarizing plate and the second polarizing plate are arranged side by side and optical compensation is performed. By integrating the layers, a large-area polarizing plate (combination polarizing plate) can be formed as a whole.

  Further, the refractive index ellipsoid of the optical compensation layer disposed on one surface side of the liquid crystal cell satisfies the relationship of nx> ny> nz, and the refractive index of the optical compensation layer disposed on the other surface side of the liquid crystal cell. The ellipsoid satisfies the relationship of nx> ny> nz. In the liquid crystal panel according to the present invention, these optical compensation layers are interposed between the liquid crystal cell and the polarizing plate, so that the viewing angle of the liquid crystal panel can be improved. Therefore, for example, it is possible to construct a liquid crystal panel with a wide viewing angle without using a separate birefringent film for the purpose of improving the viewing angle.

  The first polarizing plate and the second polarizing plate are not particularly limited as long as they have a polarizer, and a protective film may be laminated on one surface or both surfaces of the polarizer, or a polarizer and an adhesive layer. May be included. In addition, the first polarizing plate and the second polarizing plate are preferably formed in a shape having a substantially straight side (for example, a rectangular shape or a square shape), and are preferably disposed so that the end faces of the one side face each other. Is done. Further, each of the first polarizing plate and the second polarizing plate may be composed of one polarizing plate, or may be composed of two or more (a plurality of) polarizing plates. When the first polarizing plate and / or the second polarizing plate is composed of two or more polarizing plates, the two or more polarizing plates are opposed to at least one pair of end faces of adjacent polarizing plates. As described above, the optical compensation layers are arranged side by side.

  Preferably, the liquid crystal cell is a vertical alignment type (VA mode) liquid crystal cell, and a wide viewing angle of the liquid crystal panel can be realized particularly when this liquid crystal cell is used.

  Preferably, the combination type polarizing plate has a rectangular shape having a diagonal size of 80 inches or more, and can be applied to a liquid crystal cell having a diagonal size of 80 inches or more.

  The present invention is also provided as a liquid crystal display device comprising the above-described liquid crystal panel.

  The combined polarizing plate included in the liquid crystal panel according to the present invention is formed in a large area by integrating two or more polarizing plates with an optical compensation layer even if the size of the polarizer is restricted due to manufacturing restrictions. can do. Therefore, the present invention can be applied to a liquid crystal cell having a diagonal size of, for example, 80 inches or more. The liquid crystal panel according to the present invention includes an optical compensation layer in which a refractive index ellipsoid satisfies a relationship of nx> ny> nz on one surface side of the liquid crystal cell, and a refractive index on the other surface side of the liquid crystal cell. Since the ellipsoid has an optical compensation layer satisfying the relationship of nx> ny> nz, when the ellipsoid is disposed on a liquid crystal cell, particularly a vertical alignment type liquid crystal cell, a wide viewing angle of the liquid crystal panel is intended. Can do.

<Meaning of terms>
The meanings of terms used in the present invention are as follows.
“Nx” means the refractive index in the direction in which the in-plane refractive index of the film (optical compensation layer) becomes maximum (that is, the slow axis direction), and “ny” means the surface of the film (optical compensation layer). The refractive index in the direction perpendicular to the slow axis (that is, the fast axis direction). “Nz” indicates the refractive index in the thickness direction of the film (optical compensation layer).
“In-plane retardation value (Re [λ])” means an in-plane retardation value of a film (optical compensation layer) measured with light having a wavelength λ (nm) at 23 ° C. Re [λ] can be obtained by Re [λ] = (nx−ny) × d, where d (nm) is the thickness of the film (optical compensation layer).
“Thickness direction retardation value (Rth [λ])” means a thickness direction retardation value of the film (optical compensation layer) measured with light having a wavelength λ (nm) at 23 ° C. Rth [λ] can be obtained by Rth [λ] = (nx−nz) × d, where d (nm) is the thickness of the film (optical compensation layer).
The “Nz coefficient” is a value calculated from Rth [λ] / Re [λ]. In the present invention, it is a value calculated from Rth [590] / Re [590] when λ = 590 nm.
“Photoelastic coefficient” means the ease of occurrence of birefringence when an external force is applied to the film (optical compensation layer) to cause stress therein. The photoelastic coefficient is, for example, a film with a wavelength of 590 nm while applying stress to a 2 cm × 10 cm test piece at 23 ° C. using a spectroscopic ellipsometer manufactured by JASCO Corporation, product name “M-220”. (Optical compensation layer) The in-plane retardation value can be measured and calculated from the gradient of the function of the retardation value and stress.

<Outline of combined polarizing plate>
The liquid crystal panel according to the present invention includes a first optical laminated body disposed on one surface side of a liquid crystal cell and a second optical laminated body disposed on the other surface side of the liquid crystal cell. At least one of the first optical laminated body and the second optical laminated body is a combination polarizing plate. This combination type polarizing plate includes a transparent film and a first polarizing plate and a second polarizing plate arranged in parallel on one surface of the transparent film (one of the surfaces orthogonal to the thickness direction). The first polarizing plate and the second polarizing plate are transparent so that at least one pair of end surfaces of the end surfaces of the respective polarizing plates (edge portions of the polarizing plate processed into a single sheet) face each other. It is installed side by side on the film. The combination-type polarizing plate is obtained by integrating (connecting) the first polarizing plate and the second polarizing plate through the transparent film.

  In one embodiment, as shown in FIG. 1, the combination polarizing plate 10 includes a first polarizing plate 1 and a second polarizing plate 2 that are stacked on the left and right sides of a transparent film 31. Yes. The adjacent first polarizing plate 1 and second polarizing plate 2 are arranged so that one set of end faces 1a and 2a face each other.

  In another embodiment, as shown in FIG. 2, the combination polarizing plate 11 includes a first polarizing plate 1 and a second polarizing plate 2 arranged side by side between two transparent films 32 and 33. Are stacked. The adjacent first polarizing plate 1 and second polarizing plate 2 are arranged so that one set of end faces 1a and 2a face each other.

  The combination-type polarizing plate provided in the liquid crystal panel according to the present invention is bonded to the liquid crystal cell with the transparent film facing the liquid crystal cell side when disposed on the liquid crystal cell. In the case of the combined polarizing plate 11 having two transparent films 32 and 33 as shown in FIG. 2, it is bonded to the liquid crystal cell 9 with one of the transparent films 32 facing the liquid crystal cell 9 side. . Thereby, the liquid crystal panel which the transparent film intervened between the 1st polarizing plate and the 2nd polarizing plate, and the liquid crystal cell can be comprised. In the present specification, when the combination type polarizing plate is disposed on the liquid crystal cell, the transparent film interposed between the first polarizing plate and the second polarizing plate and the liquid crystal cell is referred to as “cell side”. It may be called “transparent film”.

  The first polarizing plate 1 and the second polarizing plate 2 are attached to the transparent film via the adhesive layer 5. Any appropriate layer can be selected as the adhesive layer 5 as long as the surfaces of adjacent members are joined and integrated with a practically sufficient adhesive force and adhesion time. Examples of the material for forming the adhesive layer 5 include an adhesive, a pressure-sensitive adhesive, and an anchor coating agent. The adhesive layer 5 may have a multilayer structure in which an anchor coating agent layer is formed on the surface of the adherend, and an adhesive layer or a pressure-sensitive adhesive layer is formed thereon, and may not be recognized visually. It may be a thin layer (also called a hairline).

  In particular, when the first polarizing plate 1 and the second polarizing plate 2 do not have a protective film, which will be described later, at least on the transparent film side (that is, polarized light constituting the first polarizing plate 1 and the second polarizing plate 2). When the optical element and the transparent film are directly bonded (for example, when the polarizer 4 and the transparent film 33 are bonded via the adhesive layer 5 as shown in FIG. 4 described later), the adhesive layer 5 An adhesive is preferably used as a material for forming the film. As this adhesive, an adhesive having any appropriate property, form and adhesive function can be used depending on the purpose, but water-soluble adhesive having excellent transparency, adhesiveness, workability, product quality and economic efficiency. An agent is preferably used. This water-soluble adhesive may contain, for example, at least one of a natural polymer and a synthetic polymer that are soluble in water. Examples of the natural polymer include protein and starch. Examples of the synthetic polymer include resole resin, urea resin, melamine resin, polyethylene oxide, polyacrylamide, polyvinyl pyrrolidone, acrylic acid ester, methacrylic acid ester, and polyvinyl alcohol resin. Among these, a water-soluble adhesive containing a polyvinyl alcohol resin is preferably used, and a water-soluble adhesive containing a modified polyvinyl alcohol resin having an acetoacetyl group (acetoacetyl group-containing polyvinyl alcohol resin) is more preferable. Used.

  Examples of the polyvinyl alcohol resin include a saponified product of polyvinyl acetate, a derivative of the saponified product, a saponified product of a copolymer with vinyl acetate and a copolymerizable monomer, acetalized polyvinyl alcohol, and urethane. Examples thereof include modified polyvinyl alcohols that have been converted to ethers, ethers, grafts, and phosphates. Examples of the monomer include unsaturated carboxylic acids such as maleic acid, maleic anhydride, fumaric acid, crotonic acid, itaconic acid, acrylic acid, and methacrylic acid, and esters thereof, α-olefins such as ethylene and propylene, Allyl sulfonic acid, methallyl sulfonic acid, allyl sulfonic acid soda, methallyl sulfonic acid soda, sulfonic acid soda, sulfonic acid soda monoalkyl malate, disulfonic acid soda alkyl maleate, N-methylol acrylamide, acrylamide alkyl sulfonic acid alkali salt , N-vinyl pyrrolidone, N-vinyl pyrrolidone derivatives and the like. These resins may be used alone or in combination of two or more.

  The average degree of polymerization of the polyvinyl alcohol resin is preferably in the range of 100 to 5000, and more preferably in the range of 1000 to 4000, from the viewpoint of adhesiveness. The average saponification degree of the polyvinyl alcohol resin is preferably in the range of 85 to 100 mol%, more preferably in the range of 90 to 100 mol%, from the viewpoint of adhesiveness.

  The acetoacetyl group-containing polyvinyl alcohol resin can be obtained, for example, by reacting a polyvinyl alcohol resin with diketene by an arbitrary method. Specifically, for example, a method in which diketene is added to a dispersion in which a polyvinyl alcohol resin is dispersed in a solvent such as acetic acid, diketene is dissolved in a solution in which the polyvinyl alcohol resin is dissolved in a solvent such as dimethylformamide or dioxane. The method of adding, the method of making diketene gas or liquid diketene contact directly to polyvinyl alcohol-type resin, etc. are mentioned.

  The degree of acetoacetyl group modification of the acetoacetyl group-containing polyvinyl alcohol resin is, for example, 0.1 mol% or more. By setting the degree of acetoacetyl group modification within this range, a liquid crystal panel with better water resistance can be obtained. The degree of acetoacetyl group modification is preferably in the range of 0.1 to 40 mol%, more preferably in the range of 1 to 20 mol%, and still more preferably in the range of 2 to 7 mol%. The degree of acetyl group modification is, for example, a value measured by a nuclear magnetic resonance (NMR) method.

  The water-soluble adhesive containing the polyvinyl alcohol resin may further contain a crosslinking agent. This is because the water resistance can be further improved. Any appropriate crosslinking agent can be adopted as the crosslinking agent. The cross-linking agent is preferably a compound having at least two functional groups having reactivity with the polyvinyl alcohol resin. Any appropriate crosslinking agent can be used as the crosslinking agent depending on the purpose, but amino-formaldehyde resins and dialdehydes are preferred. The amino-formaldehyde resin is preferably a compound having a methylol group. Glyoxal is preferred as the dialdehyde. Among them, a compound having a methylol group is preferable, and methylol melamine is particularly preferable.

  The amount of the crosslinking agent is, for example, in the range of 1 to 60 parts by weight with respect to 100 parts by weight of the polyvinyl alcohol resin (preferably the acetoacetyl group-containing polyvinyl alcohol resin). By making the said compounding quantity into the range of 1-60 weight part, the contact bonding layer 5 excellent in transparency, adhesiveness, and water resistance can be formed. The upper limit of the amount is preferably 50 parts by weight, more preferably 30 parts by weight, still more preferably 15 parts by weight, particularly preferably 10 parts by weight, and most preferably 7 parts by weight. is there. The lower limit of the amount is preferably 5 parts by weight, more preferably 10 parts by weight, and still more preferably 20 parts by weight. In addition, if the metal compound colloid mentioned later is used together, stability in the case where there are many compounding quantities of the said crosslinking agent can be improved further.

  The water-soluble adhesive containing the polyvinyl alcohol resin may further contain a metal compound colloid. The metal compound colloid may be, for example, one in which metal oxide fine particles are dispersed in a dispersion medium. The metal compound colloid is electrostatically stabilized due to mutual repulsion of the same kind of charge of the fine particles, and is permanently stable. It may have a property. The average particle size of the fine particles forming the metal compound is not particularly limited, but is preferably in the range of 1 to 100 nm, more preferably in the range of 1 to 50 nm. This is because the fine particles can be uniformly dispersed in the adhesive layer 5 to ensure adhesiveness and suppress the occurrence of nicks. “Knick” refers to a local irregularity defect that occurs at the bonding interface between adjacent members (for example, a polarizer and a transparent film).

  Any appropriate compound can be adopted as the metal compound. Examples of the metal compound include metal oxides such as alumina, silica, zirconia, and titania, metal salts such as aluminum silicate, calcium carbonate, magnesium silicate, zinc carbonate, barium carbonate, and calcium phosphate, celite, talc, clay, Examples include minerals such as kaolin. Of these, alumina is preferable.

  The metal compound colloid exists, for example, in the state of a colloid solution in which the metal compound is dispersed in a dispersion medium. Examples of the dispersion medium include water and alcohols. The solid content concentration in the colloidal solution is, for example, in the range of 1 to 50% by weight. The colloidal solution may contain an acid such as nitric acid, hydrochloric acid or acetic acid as a stabilizer.

  The amount of the metal compound colloid (solid content) is preferably 200 parts by weight or less with respect to 100 parts by weight of the polyvinyl alcohol resin. By making the said compounding quantity into this range, generation | occurrence | production of a nick can be suppressed more suitably, ensuring adhesiveness. The blending amount is more preferably in the range of 10 to 200 parts by weight, still more preferably in the range of 20 to 175 parts by weight, and particularly preferably in the range of 30 to 150 parts by weight.

  Any appropriate method can be adopted as a method for adjusting the adhesive. For example, in the case of an adhesive containing the metal compound colloid, for example, a method of blending the metal compound colloid into a mixture in which the polyvinyl alcohol resin and the crosslinking agent are mixed in advance and adjusted to an appropriate concentration. Is mentioned. In addition, after the polyvinyl alcohol resin and the metal compound colloid are mixed, the cross-linking agent can be mixed in consideration of the time of use.

  The resin concentration in the adhesive is preferably in the range of 0.1 to 15% by weight, more preferably in the range of 0.5 to 10% by weight, from the viewpoints of coatability and storage stability.

  The pH of the adhesive is preferably in the range of 2-6, more preferably in the range of 2.5-5, still more preferably in the range of 3-5, and particularly preferably 3.5-4. The range is 5. Generally, the surface charge of the metal compound colloid can be controlled by adjusting the pH of the adhesive. The surface charge is preferably a positive charge. By making the surface charge a positive charge, for example, the occurrence of nicks can be more suitably suppressed.

  The total solid content concentration of the adhesive varies depending on the solubility, coating viscosity, wettability, desired thickness of the adhesive 5, and the like. The total solid content concentration is preferably in the range of 2 to 100 parts by weight with respect to 100 parts by weight of the solvent. By setting the total solid content concentration within this range, the adhesive layer 5 with higher surface uniformity can be obtained. The total solid content concentration is more preferably in the range of 10 to 50 parts by weight, still more preferably in the range of 20 to 40 parts by weight.

  The viscosity of the adhesive is not particularly limited, but the value measured at a shear rate of 1000 (1 / s) at 23 ° C. is preferably in the range of 1 to 50 mPa · s. By setting the viscosity of the adhesive within this range, it is possible to obtain the adhesive layer 5 with more excellent surface uniformity. The viscosity of the adhesive is more preferably in the range of 2 to 30 mPa · s, and still more preferably in the range of 4 to 20 mPa · s.

  The glass transition temperature (Tg) of the adhesive is not particularly limited, but is preferably in the range of 20 to 120 ° C, more preferably in the range of 40 to 100 ° C, and further preferably in the range of 50 to 90 ° C. is there. The glass transition temperature can be measured, for example, by a method according to JIS K 7127-1987 by differential scanning calorimetry (DSC) measurement.

  The adhesive further includes a coupling agent such as a silane coupling agent and a titanium coupling agent, various tackifiers, an ultraviolet absorber, an antioxidant, a heat stabilizer, a hydrolysis stabilizer, and the like. May be included.

  Any appropriate method can be adopted as a method for applying the adhesive. Examples of the coating method include spin coating, roll coating, flow coating, dip coating, and bar coating.

  The thickness of the adhesive layer 5 made of an adhesive is not particularly limited, but is preferably in the range of 0.01 to 0.15 μm. By making the thickness of the adhesive layer 5 made of the adhesive in this range, a combined polarizing plate excellent in durability that does not cause peeling or lifting of the polarizer even when exposed to a high temperature and humidity environment is obtained. Can do. The thickness of the adhesive layer 5 made of the adhesive is more preferably in the range of 0.02 to 0.12 μm, and still more preferably in the range of 0.03 to 0.09 μm.

  In addition, you may provide arbitrary surface treatment and an optical member in the surface of the 1st polarizing plate 1, the 2nd polarizing plate 2, and the transparent films 31-33 in the range which does not impair the objective of this invention.

  It is preferable that the end surfaces 1a and 2a facing each other of the first polarizing plate 1 and the second polarizing plate 2 are substantially perpendicular to one surface of the polarizing plates 1 and 2, respectively. However, the end surfaces 1a and 2a may be inclined surfaces inclined with respect to one surface of the polarizing plates 1 and 2, and an appropriate end surface shape can be adopted. The first polarizing plate 1 and the second polarizing plate 2 are each preferably formed in a shape having a substantially straight side, and preferably end faces on the one side of the first polarizing plate 1 and the second polarizing plate 2. It arrange | positions so that 1a and 2a may oppose. The maximum value of the distance between the end face 1a of the first polarizing plate 1 and the end face 2a of the second polarizing plate 2 is preferably 15 μm or less, and more preferably 5 μm or less. The opposing end surfaces 1a and 2a of the first polarizing plate 1 and the second polarizing plate 2 may be connected by, for example, laser fusion or an adhesive. The total thickness of the combination polarizing plate is preferably 50 μm to 1000 μm, more preferably 100 μm to 500 μm.

  Each of the first polarizing plate and the second polarizing plate has a polarizer, and preferably further has a protective film.

  In one embodiment, as shown in FIG. 1 and FIG. 2, the first polarizing plate 1 and the second polarizing plate 2 are formed by laminating protective films 51 and 52 on both sides of the polarizer 4. Yes.

  In another embodiment, as shown in FIG. 3, the first polarizing plate 1 and the second polarizing plate 2 of the combination polarizing plate 12 are configured by laminating a protective film 53 on one surface of the polarizer 4. Yes. The first polarizing plate 1 and the second polarizing plate 2 are laminated on the cell-side transparent film 31 with the protective film 53 facing the cell-side transparent film 31 side.

  In another embodiment, as shown in FIG. 4, the first polarizing plate 1 and the second polarizing plate 2 of the combination polarizing plate 13 are configured by laminating a protective film 53 on one surface of the polarizer 4, Transparent films 32 and 33 are laminated on both surfaces of the first polarizing plate 1 and the second polarizing plate 2, respectively.

  The shape of the combined polarizing plate is not particularly limited, but is usually formed in a rectangular shape in plan view. The size of the combined polarizing plate is not particularly limited, but is preferably a rectangular shape having a diagonal size of 80 inches or more, and more preferably a rectangular shape having a diagonal size of 100 inches or more. In the combination polarizing plate, the number of the first polarizing plate and the second polarizing plate is not particularly limited, and can be appropriately selected according to the combination polarizing plate to be manufactured.

  In one embodiment, as shown in FIG. 5A, the combination polarizing plate 14 includes a long transparent film 35, a rectangular first polarizing plate 1 and a rectangular second polarizing plate. 2 are arranged in parallel with the end faces 1a, 2a on the long sides facing each other. In this case, the first polarizing plate 1 and the second polarizing plate 2 are preferably arranged so that the long side direction thereof is orthogonal to the long side direction L of the transparent film 35. Preferably, the absorption axis direction A1 of the first polarizing plate 1 and the absorption axis direction A2 of the second polarizing plate 2 are arranged substantially in parallel. The absorption axis directions A1 and A2 of the first polarizing plate 1 and / or the second polarizing plate 2 are preferably arranged substantially parallel to the short side direction M of the combination polarizing plate 14 (transparent film 35). The When a dyed stretched film is used as the polarizer, the absorption axis of the polarizer occurs in the MD direction of the dyed stretched film, and the maximum dimension of the polarizer is regulated by the dimension of the dyed stretched film in the TD direction. Therefore, in the case where a polarizer composed of a dyed stretched film is used, the absorption axis directions A1 and A2 of the first polarizing plate 1 and the second polarizing plate 2 are changed as described above. By disposing substantially parallel to the short side direction M, the combined polarizing plate 14 can be formed in a large area.

  In another embodiment, the combination polarizing plate includes a first polarizing plate and a second polarizing plate each including two or more polarizing plates. For example, as shown in FIG. 5B, such a combination-type polarizing plate 15 is arranged in a state where the end surfaces 1a ′ and 1a ″ on the long sides of the two polarizing plates 1 ′ and 1 ″ are opposed to each other. The first polarizing plate 1 provided and the second polarizing plate 2 provided side by side with the end faces 2a ′ and 2a ″ on the long sides of the two polarizing plates 2 ′ and 2 ″ facing each other are long. The long transparent film 36 is arranged in parallel in the long side direction L. In this case, preferably, the absorption axis direction A1 of each polarizing plate 1 ′, 1 ″ constituting the first polarizing plate 1 and the absorption axis direction of each polarizing plate 2 ′, 2 ″ constituting the second polarizing plate 2 are preferred. A2 is arranged substantially in parallel. The absorption axis directions A1 and A2 of the first polarizing plate 1 and / or the second polarizing plate 2 are preferably arranged substantially parallel to the long side direction L of the combined polarizing plate 15 (transparent film 36). The

  In addition, by cutting the long transparent films 35 and 36 with a cutting line parallel to the short direction M, the combination polarizing plates 14 and 15 having a rectangular shape in plan view can be obtained.

<Transparent film (optical compensation layer)>
The transparent film in this invention is used in order to integrate (connect) the 1st polarizing plate and 2nd polarizing plate which are arrange | positioned so that an end surface may oppose as one film. By using the transparent film in this way, when the first polarizing plate and the second polarizing plate are attached to the liquid crystal cell, the interval (gap) between the opposing end surfaces of each polarizing plate increases over time. Can be suppressed. For this reason, it is possible to prevent generation of light leakage from a gap (gap) between the end faces.

  When the above-mentioned first optical laminate is used as a combined polarizing plate, the transparent film constituting the first optical laminate (when transparent films are laminated on both surfaces of the first and second polarizing plates, respectively) As at least the cell-side transparent film (hereinafter the same in the description column of <transparent film>), a film (optical compensation layer) in which the refractive index ellipsoid satisfies the relationship of nx> ny> nz is used. In addition, when the above-described second optical laminate is used as a combined polarizing plate, a film in which the refractive index ellipsoid satisfies the relationship of nx> ny> nz as the transparent film constituting the second optical laminate ( An optical compensation layer) is used. Even if both the first optical laminate and the second optical laminate are combined polarizing plates, or only one of the optical laminated bodies is a combined polarizing plate, and the other optical laminated body is a normal one. Even in the configuration including a single polarizing plate, an optical compensation layer in which the refractive index ellipsoid satisfies the relationship of nx> ny> nz is disposed on one surface side of the liquid crystal cell, and the other surface of the liquid crystal cell is provided. Since the optical compensation layer whose refractive index ellipsoid satisfies the relationship of nx> ny> nz is also disposed on the side, the viewing angle of the liquid crystal panel can be improved. In particular, when these optical compensation layers are arranged in a vertical alignment type liquid crystal cell, a wide viewing angle of the liquid crystal panel can be realized.

  The transparent film preferably has a light transmittance at a wavelength of 590 nm of 80% or more, more preferably 90% or more. Further, the haze value is preferably 3% or less, more preferably 1% or less. However, the light transmittance refers to a Y value obtained by correcting the visibility based on spectral data measured with a spectrophotometer (manufactured by Hitachi, Ltd., product name: U-4100 type) with a film thickness of 100 μm. Moreover, a haze value says the value measured according to JIS-K7105.

Moreover, the absolute value of the photoelastic coefficient of the transparent film is preferably 50 × 10 ⁻¹² (m ² / N) or less, more preferably 10 × 10 ⁻¹² (m ² / N) or less. . Although the thickness of the said transparent film is not specifically limited, Since it supports a 1st polarizing plate and a 2nd polarizing plate, Preferably it forms in 20 micrometers or more. Moreover, the upper limit of the thickness of the transparent film is preferably 200 μm or less from the viewpoint of weight reduction and cost.

  The transparent film (optical compensation layer) included in the first optical laminate and the second optical laminate is a film in which the refractive index ellipsoid satisfies the relationship of nx> ny> nz. Re [590] of such a transparent film can be appropriately designed according to the purpose, but is preferably 10 nm or more, and more preferably 30 nm to 100 nm. Further, Rth [590] of this transparent film can be appropriately designed according to the purpose, but is preferably larger than 10 nm, more preferably 50 nm to 500 nm, and particularly preferably 50 nm to 400 nm. .

  In one embodiment, the transparent film preferably contains a norbornene-based polymer. In the present invention, the “norbornene polymer” refers to a (co) polymer obtained by using a norbornene monomer having a norbornene ring as a part or all of a starting material (monomer). The “(co) polymer” represents a homopolymer or a copolymer (copolymer). The transparent film is usually produced by stretching a film containing a norbornene polymer formed into a sheet shape.

In the norbornene-based polymer, a norbornene-based monomer having a norbornene ring (having a double bond in the norbornane ring) is used as a starting material. The norbornene-based polymer may or may not have a norbornane ring in the structural unit in the (co) polymer state. The norbornene-based polymer having a norbornane ring as a structural unit in the state of a (co) polymer is, for example, tetracyclo [4.4.1 ^2,5 . 1 ^7,10 . 0] Dec-3-ene, 8-methyltetracyclo [4.4.1 ^2,5 . 1 ^7,10 . 0] dec-3-ene, 8-methoxycarbonyltetracyclo [4.4.1 ^2,5 . 1 ^7,10 . 0] Dec-3-ene and the like. A norbornene-based polymer that does not have a norbornane ring as a structural unit in the (co) polymer state is, for example, a (co) polymer obtained using a monomer that becomes a 5-membered ring by cleavage. Examples of the monomer that becomes a 5-membered ring by cleavage include norbornene, dicyclopentadiene, 5-phenylnorbornene, and derivatives thereof. When the norbornene-based polymer is a copolymer, the arrangement state of the molecules is not particularly limited, and may be a random copolymer, a block copolymer, or a graft copolymer. It may be.

  Examples of the norbornene-based polymer include (a) a polymer obtained by hydrogenating a ring-opening (co) polymer of a norbornene-based monomer, and (b) a polymer obtained by addition (co) polymerization of a norbornene-based monomer. The ring-opening copolymer of (a) norbornene-based monomer is obtained by hydrogenating a ring-opening copolymer of one or more norbornene-based monomers and α-olefins, cycloalkenes, and / or non-conjugated dienes. Including polymers. The polymer obtained by addition copolymerization of the above (b) norbornene monomer is a polymer obtained by addition copolymerization of one or more norbornene monomers and α-olefins, cycloalkenes and / or nonconjugated dienes. Include.

  The polymer obtained by hydrogenating the ring-opening (co) polymer of the above (a) norbornene-based monomer is subjected to a metathesis reaction of the norbornene-based monomer or the like to obtain a ring-opening (co) polymer. It can be obtained by hydrogenating the polymer. Specifically, for example, the method described in paragraphs [0059] to [0060] of JP-A-11-116780, the method described in paragraphs [0035] to [0037] of JP-A-2001-350017, and the like. Can be mentioned. The polymer obtained by addition (co) polymerization of the (b) norbornene-based monomer can be obtained, for example, by the method described in Example 1 of JP-A No. 61-292601.

  The weight average molecular weight (Mw) of the polymer is preferably 20,000 to 500,000. However, the weight average molecular weight is a value measured by a gel permeation chromatographic method (GPC) method using a tetrahydrofuran solvent. The glass transition temperature (Tg) of the polymer is preferably 110 ° C to 180 ° C. However, the glass transition temperature (Tg) is a value determined by a DSC method according to JIS K7121. By setting the weight average molecular weight and the glass transition temperature in the above ranges, a film having good heat resistance and moldability can be obtained.

  The transparent film may be a film containing a cellulosic polymer. The film containing the polymer becomes a film exhibiting optical biaxiality of nx> ny> nz by performing a predetermined treatment.

  Examples of the cellulose polymer include cellulose polymers described in paragraphs [0106] to [0112] of JP-A-2002-82225, and paragraphs [0021] to [0034] of Japanese Patent No. 34507779. Examples include the cellulose-based polymers described.

  Cellulose polymers substituted with acetyl groups and propionyl groups can also be used. In the cellulose-based polymer, the degree of substitution of acetyl groups is “acetyl substitution degree (DSac)” indicating how many of the three hydroxyl groups present in the repeating unit of cellulose are substituted with acetyl groups on average. Can show. In the cellulose-based polymer, the degree of substitution with propionyl groups indicates “propionyl substitution degree (DSpr)” indicating how many of the three hydroxyl groups present in the repeating unit of cellulose are substituted with propionyl groups on average. Can be shown. The degree of acetyl substitution (DSac) and the degree of propionyl substitution (DSpr) can be determined by the methods described in JP-A No. 2003-315538, [0016] to [0019].

  The cellulose polymer satisfies a relational expression of 2.0 ≦ DSac + DSpr ≦ 3.0 in terms of acetyl substitution degree (DSac) and propionyl substitution degree (DSpr). The lower limit value of DSac + DSpr is preferably 2.3 or more, more preferably 2.6 or more. The upper limit value of DSac + DSpr is preferably 2.9 or less, more preferably 2.8 or less. The said cellulose polymer may have other substituents other than an acetyl group and a propionyl group. Examples of other substituents include ester groups such as petitate; ether groups such as alkyl ether groups and alkylene ether groups; The number average molecular weight of the cellulose-based polymer is preferably 5,000 to 100,000, more preferably 10,000 to 70,000. By setting it as the said range, it is excellent in productivity and favorable mechanical strength is obtained.

  In another embodiment, the transparent film of the present invention includes a transparent polymer film such as triacetyl cellulose (TAC), and an optical compensation layer directly formed by coating on the polymer film. It is also possible to have a configuration comprising:

  The optical compensation layer preferably includes at least one polymer selected from the group consisting of polyamide, polyimide, polyester, polyetherketone, polyamideimide, polyesterimide, norbornene, polycarbonate, polyolefin, and polypropylene ester.

  Then, a laminate in which the refractive index ellipsoid satisfies the relationship of nx> ny> nz is obtained by stretching a laminate obtained by applying the above polymer on a transparent polymer film such as triacetylcellulose. A film can be obtained.

<First polarizing plate and second polarizing plate>
The first polarizing plate and the second polarizing plate used in the present invention have a polarizer. Preferably, the first polarizing plate and the second polarizing plate each include a polarizer and a protective film laminated on the polarizer. This protective film is laminated on at least one surface of the polarizer, and preferably laminated on both surfaces of the polarizer.

  The polarizer is not particularly limited as long as it can convert natural light or polarized light into linearly polarized light, and a conventionally known one can be used. As the polarizer, for example, a dyed stretched film dyed with a dichroic substance, a coating film obtained by applying and drying a lyotropic liquid crystalline solution containing a dichroic substance, and the like can be used. Among them, it is preferable to use a dyed stretched film because of excellent polarization characteristics.

  The dyed stretched film is generally a stretched film mainly composed of a polyvinyl alcohol resin containing iodine or a dichroic dye. The dyed stretched film is a swelling process in which a long unstretched film mainly composed of a polyvinyl alcohol-based resin is swollen, a dyeing process in which a dichroic substance such as iodine is impregnated, and a crosslink that is crosslinked with a crosslinking agent containing boron. It can be obtained by a production method having each step of a step and a stretching step of stretching at a predetermined magnification. Although an appropriate value is appropriately selected for the thickness of the polarizer, it is preferably 5 μm to 50 μm, more preferably 10 μm to 30 μm.

  When the above-mentioned dyed stretched film is used as a polarizer, in production, the obtained polarizer has an absorption axis in the MD direction of the stretched film, and the maximum dimension of the polarizer is restricted to the dimension in the TD direction of the stretched film. Therefore, a large-area polarizing plate cannot be configured. In this respect, according to the present invention, since two or more polarizing plates are combined, a combined polarizing plate having a large area as a whole can be configured.

On the other hand, if the said protective film is excellent in transparency, it will not specifically limit, A suitable thing can be used suitably. The light transmittance of the protective film is preferably 80% or more, more preferably 90% or more. Further, the haze value is preferably 3% or less, more preferably 1% or less. In addition, the measuring method of this light transmittance and haze value is the same as that of the case of the transparent film mentioned above. Moreover, the absolute value of the photoelastic coefficient of the protective film is preferably 80 × 10 ⁻¹² (m ² / N) or less, more preferably 30 × 10 ⁻¹² (m ² / N) or less. .

  Examples of the protective film include ester polymers such as polyethylene terephthalate and polyethylene naphthalate; cellulose polymers such as diacetyl cellulose and triacetyl cellulose; acrylic polymers such as polymethyl methacrylate; polystyrene, acrylonitrile / styrene copolymer (AS Examples thereof include films of styrenic polymers such as resins); polycarbonate polymers, norbornene polymers, and the like. Although the thickness of a protective film is not specifically limited, Usually, it is about 20 micrometers-200 micrometers.

  Said protective film is affixed on a polarizer through an adhesive layer. As a material for forming the adhesive layer, a water-soluble adhesive containing a polyvinyl alcohol-based resin is used as in the adhesive used for adhering the first polarizing plate and the second polarizing plate to the transparent film. Is preferably used. In particular, when the protective film is a film made of a polymer other than a cellulose polymer such as triacetyl cellulose (for example, an acrylic polymer or a norbornene polymer), a water-soluble adhesive containing a polyvinyl alcohol resin is used. Those containing a metal compound (such as alumina) colloid are preferably used.

  In the first polarizing plate and the second polarizing plate, the protective film laminated between the cell-side transparent film and the polarizer (hereinafter sometimes referred to as “cell-side protective film”) has a refractive index ellipsoid. Those satisfying the relationship of nx> ny ≧ nz (nx> ny> nz or nx> ny = nz) may be used, and those satisfying the relationship of nx> ny> nz are preferably used. The “ny = nz” includes not only the case where ny and nz are completely the same, but also the case where they are substantially the same. When ny and nz are substantially the same, for example, (Rth [590] -Re [590]) is −10 nm to 10 nm, preferably −5 nm to 5 nm.

  By using such a cell-side protective film, the combination-type polarizing plate is disposed on the liquid crystal cell with the cell-side transparent film (the optical compensation layer whose refractive index ellipsoid satisfies the relationship of nx> ny> nz) facing the liquid crystal cell. In this case, the cell-side transparent film and the cell-side protective film are synergistic, and a wider viewing angle can be obtained. In particular, a wide viewing angle of the liquid crystal panel can be realized when it is arranged on a vertical alignment type liquid crystal cell. In the first and second polarizing plates (for example, the first and second polarizing plates shown in FIG. 1 and FIG. 2) in which protective films are laminated on both sides of the polarizer, A protective film different from the cell-side protective film (a protective film laminated on the opposite side of the cell-side transparent film across the polarizer) may be one that satisfies the relationship of nx> ny ≧ nz, Those having extremely small optical anisotropy may be used.

  In one embodiment, at least the cell-side protective film is a film in which a refractive index ellipsoid satisfies a relationship of nx> ny = nz. Re [590] of this cell side protective film is 10 nm or more, preferably 50 nm to 300 nm, more preferably 50 nm to 200 nm. Moreover, the difference (Rth [590] −Re [590]) between the thickness direction retardation value and the in-plane retardation value of the cell-side protective film is less than 10 nm, preferably less than 5 nm. Further, the Nz coefficient of the cell-side protective film is preferably more than 0.9 and less than 1.1.

  In another embodiment, at least the cell-side protective film is a film whose refractive index ellipsoid satisfies the relationship of nx> ny> nz. Re [590] of this cell side protective film is 10 nm or more, preferably 50 nm to 300 nm, more preferably 50 nm to 200 nm. Moreover, the difference (Rth [590] -Re [590]) between the thickness direction retardation value and the in-plane retardation value of the cell-side protective film is 10 nm or more, and preferably 20 nm to 100 nm. Furthermore, the Nz coefficient of the cell-side protective film is preferably 1.1 to 3.0.

  It is preferable that at least the cell-side protective film is a film containing a norbornene-based polymer or a cellulose-based polymer, or obtained by applying a polymer such as polyimide on a transparent polymer film such as triacetylcellulose. Since the point which can be formed by extending | stretching a laminated body is the same as that of the case of the transparent film mentioned above, the detailed description is abbreviate | omitted here.

  In the first and second polarizing plates (for example, the first and second polarizing plates shown in FIG. 1 and FIG. 2) in which protective films are laminated on both sides of the polarizer, Examples of the protective film different from the cell-side protective film include those having a refractive index ellipsoid of nx> ny ≧ nz, nx <ny = nz, nx = ny> nz, nx> nz> ny, nz> nx> A material satisfying the ny relationship or an isotropic material may be used.

<LCD panel>
The liquid crystal panel of the present invention includes a liquid crystal cell, a first optical laminate disposed on one surface side of the liquid crystal cell, and a second optical laminate disposed on the other surface side of the liquid crystal cell. . At least one of the first optical laminated body and the second optical laminated body is the combination polarizing plate described above. This combination type polarizing plate is disposed on at least one surface of the liquid crystal cell with the cell-side transparent film facing the liquid crystal cell side.

  In one embodiment, as illustrated in FIG. 6A, the liquid crystal panel 100 includes a liquid crystal cell 9, a first optical laminate A disposed on one surface side of the liquid crystal cell 9, and the liquid crystal cell 9. 2nd optical laminated body B arrange | positioned at the other surface side. In the present embodiment, only the second optical laminate B is a combined polarizing plate.

  The first optical laminated body A is disposed between one arbitrary polarizing plate 7 disposed on one surface side of the liquid crystal cell 9 and between the liquid crystal cell 9 and the one polarizing plate 7 and has a refractive index. The ellipsoid has a transparent film 38 as an optical compensation layer satisfying the relationship of nx> ny> nz.

  The second optical laminate B includes the other polarizing plate (the first polarizing plate 1 and the second polarizing plate 2) disposed on the other surface side of the liquid crystal cell 9, and the liquid crystal cell 9 and the other polarizing plate. Transparent film (transparent on the cell side) as an optical compensation layer disposed between polarizing plates (first polarizing plate 1 and second polarizing plate 2) and having a refractive index ellipsoid satisfying the relationship of nx> ny> nz Film) 37. The second optical layered body B constitutes a combined polarizing plate 16 in which the first polarizing plate 1 and the second polarizing plate 2 are arranged side by side on a single transparent film 37.

  In another embodiment, as shown in FIG. 6B, the liquid crystal panel 100 includes a liquid crystal cell 9, a first optical laminate A disposed on one surface side of the liquid crystal cell 9, and the liquid crystal cell 9. 2nd optical laminated body B arrange | positioned at the other surface side. In the present embodiment, both the first optical laminate A and the second optical laminate B are combined polarizing plates.

  The first optical laminate A includes one polarizing plate (first polarizing plate 1 and second polarizing plate 2) disposed on one surface side of the liquid crystal cell 9, and the liquid crystal cell 9 and the one of the one Transparent film (transparent on the cell side) as an optical compensation layer disposed between polarizing plates (first polarizing plate 1 and second polarizing plate 2) and having a refractive index ellipsoid satisfying the relationship of nx> ny> nz Film) 38. The first optical laminated body A constitutes a combined polarizing plate 17 in which the first polarizing plate 1 and the second polarizing plate 2 are arranged side by side on a single transparent film 38.

  The second optical laminate B includes the other polarizing plate (the first polarizing plate 1 and the second polarizing plate 2) disposed on the other surface side of the liquid crystal cell 9, and the liquid crystal cell 9 and the other polarizing plate. Transparent film (transparent on the cell side) as an optical compensation layer disposed between polarizing plates (first polarizing plate 1 and second polarizing plate 2) and having a refractive index ellipsoid satisfying the relationship of nx> ny> nz Film) 37. The second optical layered body B constitutes a combined polarizing plate 16 in which the first polarizing plate 1 and the second polarizing plate 2 are arranged side by side on a single transparent film 37.

  In the liquid crystal panel 100 shown in FIG. 6, the first optical laminated body A and the second optical laminated body B include the absorption axis direction of the polarizing plate constituting the first optical laminated body A and the second optical laminated body B. Are arranged so that the absorption axis directions of the polarizing plates constituting the plate are orthogonal to each other. Further, the polarizing plate and the transparent film (optical compensation layer) constituting the first optical laminate A are so that the absorption axis direction of the polarizing plate and the slow axis direction of the transparent film (optical compensation layer) are orthogonal to each other. Be placed. Similarly, in the polarizing plate and the transparent film (optical compensation layer) constituting the second optical laminate B, the absorption axis direction of the polarizing plate and the slow axis direction of the transparent film (optical compensation layer) are orthogonal to each other. Are arranged as follows.

  In addition, in FIG. 6, although the combination type polarizing plate which comprises one transparent film is illustrated, it is a combination polarizing plate which comprises two transparent films as shown in FIG. 2 and FIG. Also good. 6A shows a liquid crystal panel having a configuration in which the combination type polarizing plate is disposed below the liquid crystal cell 9, the combination type polarizing plate is disposed above the liquid crystal cell 9. FIG. It may be a liquid crystal panel. Further, FIG. 6 shows a liquid crystal panel having a configuration in which the first optical laminated body A is disposed on the upper side of the liquid crystal cell 9 and the second optical laminated body B is disposed on the lower side of the liquid crystal cell 9. However, a liquid crystal panel in which the first optical laminate A is disposed below the liquid crystal cell 9 and the second optical laminate B is disposed above the liquid crystal cell 9 may be used.

  As the liquid crystal cell used in the present invention, any appropriate one can be adopted. Examples of the liquid crystal cell include an active matrix liquid crystal cell using a thin film transistor and a simple matrix liquid crystal cell typified by a super twist nematic liquid crystal display device.

  The liquid crystal cell preferably includes a pair of substrates and a liquid crystal layer as a display medium sandwiched between the pair of substrates. One substrate (active matrix substrate) includes a switching element (typically a TFT) for controlling the electro-optical characteristics of the liquid crystal, a scanning line for supplying a gate signal to the switching element, and a signal line for supplying a source signal. Provided. The other substrate (color filter substrate) is provided with a color filter. The color filter may be provided on the active matrix substrate. However, when RGB three-color light sources are used as the illumination means of the liquid crystal display device as in the field sequential method, the color filter can be omitted. The distance between the two substrates is controlled by a spacer. For example, an alignment film made of polyimide is provided on the side of each substrate in contact with the liquid crystal layer.

  The liquid crystal cell preferably includes a nematic liquid crystal aligned in a homeotropic alignment in the absence of an electric field, and is, for example, a vertical alignment (VA mode) liquid crystal cell.

  A vertically aligned liquid crystal cell uses a voltage-controlled birefringence (ECB) effect, and nematic liquid crystal with negative dielectric anisotropy is homeotropically arranged between transparent electrodes when no voltage is applied. It refers to a liquid crystal cell that is aligned in the direction. Specific examples include liquid crystal cells described in JP-A-62-210423 and JP-A-4-153621. Further, as described in JP-A-11-258605, the above-mentioned vertical alignment type liquid crystal cell has a structure in which a slit is provided in a pixel or a projection is formed on the surface in order to enlarge a viewing angle. A multi-domain MVA mode liquid crystal cell may be used by using a material. Further, as described in JP-A-10-123576, a VATN mode in which a chiral agent is added to a liquid crystal, nematic liquid crystal is substantially vertically aligned when no voltage is applied, and twisted multi-domain alignment is applied when a voltage is applied. The liquid crystal cell may be used. The combination polarizing plate of the present invention is not limited to being applied to a vertical alignment type liquid crystal cell, and may be applied to, for example, an IPS mode liquid crystal cell.

<Liquid crystal display device>
The liquid crystal display device of the present invention includes the liquid crystal panel described above. FIG. 7 shows a configuration example of a liquid crystal display device. The liquid crystal display device 200 includes at least one liquid crystal panel 100 of which various examples are illustrated with reference to FIG. 6 as described above, and a backlight unit 80 disposed on one side of the liquid crystal panel 100. Note that FIG. 7 shows a case where the direct type is adopted as the backlight unit, but the light unit may be, for example, a side light type.

  When the direct type is adopted, the backlight unit 80 preferably includes at least a light source 81, a reflection film 82, a diffusion plate 83, a prism sheet 84, and a brightness enhancement film 85. When the sidelight method is adopted, preferably, the backlight unit further includes at least a light guide plate and a light reflector in addition to the above-described configuration. Note that the liquid crystal display device illustrated in FIG. 7 may be partially omitted depending on the application, such as the illumination method of the liquid crystal display device and the drive mode of the liquid crystal cell, as long as the effects of the present invention can be obtained. It is possible to substitute a part of it for another member.

  The liquid crystal display device may be a transmissive type that irradiates light from the back surface of the liquid crystal panel to view the screen, or a reflective type that irradiates light from the viewing side of the liquid crystal panel to view the screen. Alternatively, the liquid crystal display device may be a transflective type having both transmissive and reflective properties.

  The liquid crystal panel and the liquid crystal display device of the present invention are used for any appropriate application. Applications of the liquid crystal panel and liquid crystal display device include, for example, OA equipment such as a personal computer monitor, notebook personal computer, and copy machine, mobile equipment such as a mobile phone, a clock, a digital camera, a personal digital assistant (PDA), and a portable game machine, video Household electrical equipment such as cameras, televisions and microwave ovens, back monitors, car navigation system monitors, car audio equipment and other in-vehicle equipment, display equipment such as commercial store information monitors, security equipment such as monitoring monitors, nursing care Nursing care and medical equipment such as medical monitors and medical monitors.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.

<Various measurement methods>
(1) Measuring method of transmittance (T [590]):
Measurement was performed using a high-speed spectrophotometer (Murakami Color Difference Co., Ltd., product name “CMS-500”).
(2) Measuring method of nx, ny, nz, Re [590] and Rth [590]:
It measured at 23 degreeC using the product name "KOBRA21-ADH" by Oji Scientific Instruments. In addition, the value measured using the Abbe refractometer (The product made from Atago Co., Ltd. product name "DR-M4") was used for the average refractive index.
(3) Method of measuring contrast of liquid crystal display device (measurement of luminance viewing angle characteristics):
In a dark room at 23 ° C., 30 minutes after turning on the backlight, measurement was performed using a product name “EZ Contrast 160D” manufactured by ELDIM.

<Example 1>
<Preparation of optical compensation layer (transparent film)>
A norbornene-based film (trade name “ZEONOR” manufactured by Nippon Zeon Co., Ltd., thickness 100 μm) is 1.3 times in a uniaxial direction (X-axis direction) at 145 ° C., and a direction perpendicular to the uniaxial direction (Y-axis direction) The film was stretched 1.05 times to obtain a transparent film. In the obtained transparent film, the refractive index ellipsoid showed a relationship of nx>ny> nz, and Re [590] = 52 nm and Rth [590] = 160 nm. Further, the light transmittance (T [590]) of the obtained transparent film was 92%.

<Preparation of polarizing plate (first polarizing plate and second polarizing plate)>
A roll stretching machine is used to roll a polymer film (made by Kuraray Co., Ltd., trade name “9P75R”, average polymerization degree: 2400) containing polyvinyl alcohol having a thickness of 75 μm as a main component in a dyeing bath containing iodine and potassium iodide. The resulting film was uniaxially stretched 6 times the original length while being dyed to produce a 28 μm thick polarizer.

Next, a cellulose film (manufactured by Fuji Photo Film Co., Ltd., trade name “ZRF80S”, thickness 80 μm) was attached to both surfaces of the polarizer via an adhesive. Thus, the polarizing plate by which the protective film (cellulose-type film) was laminated | stacked on both surfaces of the polarizer was produced. “ZRF80S” was Re [590] ≈0 nm and Rth [590] ≈0 nm.

<Preparation of liquid crystal cell>
A liquid crystal panel was taken out from a liquid crystal display device (liquid crystal television manufactured by Sony Corporation, trade name “BRAVIA S2000”, screen size: 32 inches) including a VA mode liquid crystal cell. From the liquid crystal panel, the optical films arranged above and below the liquid crystal cell were all removed, and the glass surfaces (front and back) of the obtained liquid crystal cell were washed.

<Preparation of optical laminate (combination polarizing plate)>
Two sheets of the polarizing plate produced as described above were prepared by punching into a rectangular shape. The two polarizing plates are arranged on the surface of the transparent film (norbornene-based stretched film) prepared as described above so that the absorption axes of the two polarizing plates are parallel to each other and the end faces of the two polarizing plates face each other. Each polarizing plate and the transparent film were stuck through a 20 μm thick adhesive. In addition, it stuck so that the absorption axis of each polarizing plate and the slow axis of a transparent film might be orthogonal at this time. Moreover, one protective film of the two polarizing plates was stuck toward the surface of the transparent film.

  As described above, two optical laminates (combined polarizing plates) having a configuration in which two polarizing plates arranged together were integrated with one transparent film were produced. These combination type polarizing plates were punched out so as to match the screen size of the liquid crystal cell, and were used as a first optical laminate and a second optical laminate, respectively.

<Production of liquid crystal panel>
On the viewing side of the liquid crystal cell taken out in the above <Preparation of liquid crystal cell>, the first optical laminate prepared above is acrylic adhesive (thickness) with its transparent film (optical compensation layer) facing the liquid crystal cell side. 20 μm). Further, the second optical layered body manufactured above is directed to the backlight side of the liquid crystal cell, the transparent film (optical compensation layer) is directed to the liquid crystal cell side, and the absorption axis of the polarizing plate is the first optical layer. A liquid crystal panel was produced by pasting together via an acrylic pressure-sensitive adhesive (thickness 20 μm) so as to be orthogonal to the absorption axis of the polarizing plate of the laminate.

<Production of liquid crystal display device>
The liquid crystal panel was combined with a backlight unit included in the original liquid crystal display device to produce a liquid crystal display device.

<Evaluation of luminance viewing angle characteristics of liquid crystal display devices>
The luminance viewing angle characteristics of the liquid crystal display device of Example 1 manufactured as described above were measured using a product name “EZ Contrast 160D” manufactured by ELDIM. The result is shown in FIG. As shown in FIG. 8, light leakage was small in all directions, and excellent display characteristics were shown. In this example, a liquid crystal cell having a diagonal size of 32 inches was used to evaluate the display characteristics of the liquid crystal display device. However, if the combination type polarizing plate provided in the liquid crystal panel of the present invention is used, the diagonal size is 80. It can also be applied to liquid crystal cells exceeding inches.

<Example 2>
<Preparation of optical compensation layer (transparent film)>
On one side of a triacetylcellulose (TAC) film (Fuji Photo Film Co., Ltd., trade name “ZRF80S”, thickness 80 μm), a solution of polyimide dissolved in cyclohexanone solvent (polyimide concentration 15% by mass) at a thickness of 18 μm Coated. Then, it dried at 100 degreeC for 10 minute (s), and formed the polyimide layer about 2.5 micrometers thick. As this polyimide, one synthesized from 2,2′-bis (3,4-dicarboxyphenyl) hexafluoropropane and 2,2′-bis (trifluoromethyl) -4,4′-diaminobiphenyl was used. . The laminated film in which the polyimide layer was laminated on the TAC film had Re [590] = 0.4 nm and Rth [590] = 101 nm.

  Next, a transparent film was produced by stretching the above-mentioned laminated film at 160 ° C. in a uniaxial direction (X-axis direction) at a stretching ratio of 1.2 times. In the obtained transparent film, the refractive index ellipsoid showed a relationship of nx> ny> nz, and Re [590] = 50 nm and Rth [590] = 162 nm. Further, the light transmittance (T [590]) of the obtained transparent film was 91%.

<Production of liquid crystal display device>
A liquid crystal display device was produced in the same manner as in Example 1 except that a film obtained by stretching a laminate of a TAC film and a polyimide layer was used as the transparent film.

<Evaluation of luminance viewing angle characteristics of liquid crystal display devices>
The luminance viewing angle characteristics of the liquid crystal display device of Example 2 produced as described above were measured using a product name “EZ Contrast 160D” manufactured by ELDIM. The result is shown in FIG. As shown in FIG. 9, light leakage was small in all directions, and excellent display characteristics were exhibited. In this example, a liquid crystal cell having a diagonal size of 32 inches was used to evaluate the display characteristics of the liquid crystal display device. However, if the combination type polarizing plate provided in the liquid crystal panel of the present invention is used, the diagonal size is 80. It can also be applied to liquid crystal cells exceeding inches.

FIG. 1 is a longitudinal sectional view showing an embodiment of a combined polarizing plate provided in the liquid crystal panel of the present invention. FIG. 2 is a longitudinal sectional view showing another embodiment of the combination polarizing plate provided in the liquid crystal panel of the present invention. FIG. 3 is a longitudinal sectional view showing another embodiment of the combination polarizing plate provided in the liquid crystal panel of the present invention. FIG. 4 is a longitudinal sectional view showing another embodiment of the combined polarizing plate provided in the liquid crystal panel of the present invention. FIG. 5A is a partially omitted plan view showing an embodiment of a combined polarizing plate including a long transparent film. FIG. 5B is a partially omitted plan view showing another embodiment of the combined polarizing plate including a long transparent film. FIG. 6A is a longitudinal sectional view showing an embodiment of the liquid crystal panel of the present invention. FIG. 6B is a longitudinal sectional view showing another embodiment of the liquid crystal panel of the present invention. FIG. 7 is a longitudinal sectional view showing an embodiment of the liquid crystal display device of the present invention. FIG. 8 is a luminance contour diagram showing measurement results of luminance viewing angle characteristics of the liquid crystal display device according to Example 1 of the present invention. FIG. 9 is a luminance contour diagram showing measurement results of luminance viewing angle characteristics of the liquid crystal display device according to Example 2 of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... 1st polarizing plate 1a ... End surface of 1st polarizing plate 2 ... 2nd polarizing plate 2a ... End surface of 2nd polarizing plate 31-38 ... Transparent film 4 ... Polarizer 51-53 ... Protective film 5 ... Adhesive layer 9 ... Liquid crystal cell 10-17 ... Combination type polarizing plate 100 ... Liquid crystal panel 200 ... Liquid crystal display device A ... First optical laminate B ... Second optical laminate

Claims (4)

A liquid crystal cell;
One polarizing plate disposed on one surface side of the liquid crystal cell, and the refractive index ellipsoid disposed between the liquid crystal cell and the one polarizing plate satisfy a relationship of nx>ny> nz. A first optical laminate comprising an optical compensation layer;
The other polarizing plate disposed on the other surface side of the liquid crystal cell, and the refractive index ellipsoid disposed between the liquid crystal cell and the other polarizing plate satisfy a relationship of nx>ny> nz. A second optical laminate comprising an optical compensation layer,
At least one of the first optical laminated body and the second optical laminated body is arranged side by side on the surface opposite to the liquid crystal cell of the optical compensation layer so that at least one pair of end faces face each other. A liquid crystal panel comprising a combination polarizing plate having a first polarizing plate and a second polarizing plate.   The liquid crystal panel according to claim 1, wherein the liquid crystal cell is a vertical alignment type liquid crystal cell.   The liquid crystal panel according to claim 1, wherein the combined polarizing plate has a rectangular shape having a diagonal size of 80 inches or more.   A liquid crystal display device comprising the liquid crystal panel according to claim 1.