Polarizing plate and optical display device including the same

Abstract

To provide a polarizing plate capable of improving visibility at the full viewing angle and minimizing color change.SOLUTION: Provided is a polarizing plate that includes a polarizer and a retardation layer laminated on one surface of the polarizer. The retardation layer includes a retardation film having nx>nz>ny at a wavelength of 550 nm (nx, ny and nz are the refractive indexes of the retardation film at the wavelength of 550 nm in a slow axis direction, in a fast axis direction and in the thickness direction, respectively). The alignment direction of the main chain of a resin included in the retardation film forms -5° to +5° to the light transmission axis of the polarizer; the retardation film has 0.2-0.6 of the level of biaxiality at a wavelength of 550 nm. An optical display device that includes the polarizing plate is also provided.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a polarizing plate and an optical display device including the same. [Background technology]

[0002] An LCD comprises a liquid crystal panel as an optical display panel, a viewer-side polarizing plate laminated on the upper surface of the liquid crystal panel, and a light source-side polarizing plate laminated on the lower surface of the liquid crystal panel. Among the driving methods for LCD panels, the in-plane electric field method drives the liquid crystal compound in the in-plane direction of the substrate by an electric field that includes a component approximately parallel to the substrate surface of the LCD panel. The in-plane electric field method includes the IPS and FFS methods. The in-plane electric field method can increase the contrast ratio and viewing angle and minimize color change by providing a retardation layer between the liquid crystal panel and the polarizer.

[0003] According to one embodiment, the retardation layer may be a laminate of a positive C (+C) layer and a positive A (+A) layer. For example, the polarizing plate may be laminated in the order of a polarizer, a positive C (+C) layer, an adhesive layer, and a positive A (+A) layer. However, such a polarizing plate has two retardation layers, a positive C (+C) layer and a positive A (+A) layer. Therefore, in order to obtain the effect of making the polarizing plate thinner, it is preferable to make the retardation layer a single layer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Korean Patent Publication No. 2013-0103595 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a polarizing plate having a single-layer retardation film, which improves visibility over the entire viewing angle and minimizes color change.

[0006] An object of the present invention is to provide a polarizing plate having a single-layer retardation film and reducing light leakage by lowering the maximum light transmittance in a black mode over the entire viewing angle.

[0007] An object of the present invention is to provide a polarizing plate which is provided with a single-layer retardation film and which exhibits an excellent effect of reducing the thickness.

[0008] An object of the present invention is to provide a polarizing plate which includes a single-layer retardation film and can be manufactured with a large width in the lateral direction. [Means for solving the problem]

[0009] According to one embodiment, the polarizing plate includes a polarizer and a retardation layer laminated on one side of the polarizer, the retardation layer includes a retardation film having nx>nz>ny (nx, ny, and nz are the refractive indexes of the retardation film in the slow axis direction, the fast axis direction, and the thickness direction at a wavelength of 550 nm) at a wavelength of 550 nm, the orientation direction of the main chain of the resin included in the retardation film is at an angle of -5° to +5° relative to the light transmission axis of the polarizer, and the retardation film has a degree of biaxiality of 0.2 to 0.6 at a wavelength of 550 nm.

[0010] According to one embodiment, an optical display device includes the polarizer. Effect of the Invention

[0011] It is possible to provide a polarizing plate having a single layer of retardation film, which improves visibility over the entire viewing angle and minimizes color change.

[0012] It is possible to provide a polarizing plate having a single-layer retardation film and reducing the maximum light transmittance in the black state over the entire viewing angle, thereby improving light leakage.

[0013] It is possible to provide a polarizing plate that has a single layer of retardation film and exhibits an excellent effect of reducing the thickness.

[0014] It is possible to provide a polarizing plate that has a single layer of retardation film and can be manufactured with a wide width in the lateral direction. [Brief description of the drawings]

[0015] [Figure 1] FIG. 2 is a cross-sectional view of a polarizing plate according to an embodiment. [Diagram 2] FIG. 11 is a cross-sectional view of a polarizing plate according to another embodiment. [Diagram 3] The figure shows the maximum light transmittance (Y-axis, unit: %) at the entire viewing angle according to the degree of biaxiality (NZ) of the retardation film at a wavelength of 550 nm and the in-plane retardation (X-axis, unit: nm) at a wavelength of 550 nm when a polarizing plate according to one embodiment is mounted on a horizontal electric field type device and driven. (■: Light transmittance when the retardation film has an NZ of 0.4 at a wavelength of 550 nm, ●: when the retardation film has an NZ of 0.5 at a wavelength of 550 nm, ▲: when the retardation film has an NZ of 0.6 at a wavelength of 550 nm.) [Figure 4] 1 shows the light transmittance when the polarizing plate of Example 1 is driven. [Diagram 5] This shows the hue value when the polarizing plate of Example 1 is driven. [Figure 6] 13 shows the light transmittance when the polarizing plate of Comparative Example 2 is driven. [Figure 7] 4 shows the hue value when the polarizing plate of Comparative Example 2 was driven. [Figure 8] 13 shows the light transmittance when the polarizing plate of Comparative Example 3 is driven. [Figure 9] 4 shows the hue value when the polarizing plate of Comparative Example 3 was driven. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings, in which: FIG.

[0017] In the drawings, in order to clearly explain the present invention, parts not related to the description are omitted, and the same reference numerals are used to refer to the same or similar components throughout the specification. The length and size of each component in the drawings are for the purpose of explaining the present invention, and the present invention is not limited to the length and size of each component shown in the drawings.

[0018] The terms used herein are merely used to describe exemplary embodiments and are not intended to limit the present invention. A singular expression includes a plural expression unless otherwise clearly indicated in the context.

[0019] In this specification, "in-plane retardation (Re)" is represented by the following formula A, "thickness direction retardation (Rth)" is represented by the following formula B, and "degree of biaxiality (NZ)" is represented by the following formula C. [Formula A] Re = (nx-ny) × d [Formula B] Rth = ((nx + ny) / 2-nz) × d [Formula C] NZ = (nx-nz) / (nx-ny)

[0020] In formulas A to C, nx, ny, and nz are the refractive indices in the slow axis direction, fast axis direction, and thickness direction of the optical element at the measurement wavelength, respectively, and d is the thickness (unit: nm) of the optical element. In formulas A to C, the measurement wavelength may be any specific wavelength between 450 nm and 650 nm.

[0021] In this specification, unless otherwise specified, nx, ny, and nz respectively refer to the slow axis (the axis in the in-plane direction in which the refractive index is maximum), the fast axis (the axis in the in-plane direction in which the refractive index is minimum), and the refractive index in the thickness direction of an optical element at a wavelength of 550 nm.

[0022] In this specification, when describing angles, "+" means a counterclockwise direction relative to a reference, and "-" means a clockwise direction relative to a reference.

[0023] In this specification, "light transmittance" means total transmittance rather than cross light transmittance.

[0024] As used herein, "(meth)acrylic" means acrylic and / or methacrylic.

[0025] In this specification, when a numerical range is indicated, "X to Y" means "X or more and Y or less (X≦and≦Y)."

[0026] A polarizing plate according to an embodiment includes a single-layer retardation film. The polarizing plate improves visibility over the entire viewing angle, minimizes color change, reduces the maximum light transmittance in a black state over the entire viewing angle to improve light leakage, and has an excellent effect of reducing thickness. Here, "reducing the maximum light transmittance" means that when the polarizing plate is applied to an optical display device and driven, the degree of light transmission in a black mode over the entire viewing angle is reduced to prevent light leakage.

[0027] In one embodiment, the lower the maximum light transmittance, the more preferable. The maximum light transmittance may be 0.9% or less, for example, 0 to 0.5%, 0 to 0.3%, 0.1 to 0.4%, or 0.1 to 0.3%.

[0028] A polarizing plate according to one embodiment includes a single-layer retardation film, which can be manufactured to have a wide width in the width direction, thereby improving processability and cost efficiency when manufacturing the polarizing plate.

[0029] A polarizing plate according to one embodiment includes a polarizer and a retardation layer laminated on one surface of the polarizer. The retardation layer includes a retardation film in which nx>nz>ny (nx, ny, and nz are the refractive indexes of the retardation film in the slow axis direction, fast axis direction, and thickness direction at a wavelength of 550 nm) at a wavelength of 550 nm, the orientation direction of the main chain of a resin included in the retardation film is at an angle of -5° to +5° relative to the light transmission axis of the polarizer, and the retardation film has a degree of biaxiality of 0.2 to 0.6 at a wavelength of 550 nm.

[0030] The polarizing plate may be a viewer-side polarizing plate or a light source-side polarizing plate.

[0031] According to one embodiment, the retardation layer may be located between the polarizer of the viewer-side polarizing plate and a panel for an optical display device (e.g., a liquid crystal panel). Preferably, the light absorption axis of the polarizer in the viewer-side polarizing plate and the alignment direction of the liquid crystal of the panel may be substantially perpendicular to each other.

[0032] According to another embodiment, the retardation layer may be located between the polarizer of the light source side polarizing plate and the panel for optical display device. Preferably, the light absorption axis of the polarizer in the light source side polarizing plate and the alignment direction of the liquid crystal of the panel may be substantially perpendicular to each other.

[0033] The retardation film is a single-layer retardation film. This has the effect of reducing the thickness of the polarizing plate and improving the workability and profitability during the manufacture of the polarizing plate. Here, the "single-layer retardation film" means a retardation film consisting of only one layer, without two or more layers of retardation film being bonded together by an adhesive layer or bonding layer.

[0034] According to one embodiment, the retardation film may have a thickness of 40 to 100 μm, for example, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, for example, 40 to 80 μm. In this range, it can be applied to a polarizing plate, and can provide an effect of reducing the thickness.

[0035] The retardation layer may be composed of only a retardation film, which has the effect of reducing the thickness of the polarizing plate and improving the workability and profitability during the manufacture of the polarizing plate.

[0036] According to one embodiment, the polarizing plate may have only a retardation film between the polarizer and the adherend (e.g., a panel for an optical display device). In this case, the polarizing plate may have an adhesive layer, a retardation film, and an adhesive layer laminated in this order on one side of the polarizer, and the adhesive layer may be adhered to the adherend.

[0037] According to another embodiment, the polarizing plate may have a retardation film and one or more lower protective layers between the polarizer and the adherend (e.g., a panel for an optical display device). The lower protective layer may be interposed between the polarizer and the retardation film and / or between the retardation film and the adherend. In one embodiment, the polarizing plate may have an adhesive layer, a retardation film, a lower protective layer, and an adhesive layer laminated in this order on one side of the polarizer, and the adhesive layer may be adhered to the adherend.

[0038] The lower protective layer may have an in-plane retardation of 10 nm or less at a wavelength of 550 nm, for example, 0 nm, 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, for example, 0 to 10 nm. In this range, the protective effect of the polarizer can be provided without affecting the function and effect of the retardation film. The lower protective layer may be an optically transparent film or coating layer. For example, the lower protective layer may be a film made of one or more resins selected from cellulose-based materials including triacetyl cellulose (TAC) and the like, polyester-based materials including polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, and the like, cyclic olefin copolymer (COC)-based materials, cyclic olefin polymer (COP)-based materials, polycarbonate-based materials, polyethersulfone-based materials, polysulfone-based materials, polyamide-based materials, polyimide-based materials, polyolefin-based materials, polyarylate-based materials, polyvinyl alcohol-based materials, polyvinyl chloride-based materials, polyvinylidene chloride-based materials, and acrylic-based materials.

[0039] The retardation film has a refractive index of nx>nz>ny at a wavelength of 550nm (nx, ny, and nz are the refractive indexes of the retardation film in the slow axis direction, fast axis direction, and thickness direction at a wavelength of 550nm), and the orientation direction of the main chain of the resin contained in the retardation film is -5° to +5° relative to the light transmission axis of the polarizer. This makes it easy to provide the effect of improving visibility at all viewing angles, minimizing color change, and lowering light transmittance in the black state at all viewing angles even if the polarizing plate has a single layer of retardation film.

[0040] The retardation film has nx>nz>ny at a wavelength of 550 nm. This means that by making nx>ny and 0<(nx-nz) / (nx-ny)<1, the retardation film has little change due to the viewing angle when used, and when applied to a birefringent optical display panel, it can be useful for improving the visibility in the brightness ratio or black and white display and reducing color change.

[0041] According to an embodiment, (nx-ny) may be 0.0022 to 0.0075, for example, 0.0028 to 0.0075, and (nx-nz) may be 0.00044 to 0.0045, for example, 0.00066 to 0.0038. In this range, when the retardation film is used, the change due to the viewing angle is small, and when applied to a birefringent optical display panel, it can be useful for improving the brightness ratio or visibility in black and white display.

[0042] According to one embodiment, nx of the retardation film may be 1.500 to 1.710, for example, 1.500, 1.550, 1.600, 1.650, 1.700, 1.710, for example, 1.500 to 1.705, ny may be 1.480 to 1.700, for example, 1.480, 1.500, 1.550, 1.600, 1.650, 1.700, for example, 1.485 to 1.700, and nz may be 1.500 to 1.705, for example, 1.500, 1.550, 1.600, 1.650, 1.700, 1.705, for example, 1.500 to 1.700. In this range, the above-mentioned ranges of nx-ny and nx-nz can be easily reached, and the retardation film can be easily manufactured.

[0043] In the retardation film, the orientation direction of the main chain of the resin contained in the retardation film is -5° to +5° relative to the light transmission axis of the polarizer. This is because the retardation film is manufactured using a composition for retardation film described below, and the retardation film satisfies the optical properties described below, thereby improving visibility over the entire viewing angle and providing an effect of reducing light transmittance in the black state over the entire viewing angle.

[0044] According to one embodiment, the orientation direction of the main chain of the resin contained in the retardation film may be -3° to +3°, 0° relative to the light transmission axis of the polarizer. In this range, the above-mentioned effects can be obtained, and the manufacturing processability of the polarizing plate by roll-to-roll can be improved since the mechanical direction of the retardation film and the mechanical direction of the polarizer are substantially parallel.

[0045] The main chain direction of the resin contained in the retardation film can be measured by a conventional method known to those skilled in the art. For example, the main chain orientation direction can be confirmed by visually confirming the crystal orientation in the stretching direction of the retardation film. For example, the main chain orientation direction can be confirmed by measuring the crystal structure of the resin in the retardation film by X-ray measurement of the retardation film, measuring the dynamic structure of the resin in the retardation film by NMR measurement of the retardation film, and measuring the orientation direction through Raman and infrared spectroscopy. The light transmission axis of the polarizer may be the transverse direction of the polarizer.

[0046] The angle between the orientation direction of the main chain of the resin contained in the retardation film and the light transmission axis of the polarizer can be realized by adjusting the angle between the main chain direction and the light transmission axis of the polarizer when laminating the retardation film on the polarizer.

[0047] According to one embodiment, the retardation film has a biaxial degree of 0.2 to 0.6 at a wavelength of 550 nm. If the biaxial degree is less than 0.2, the light transmittance in the black state increases at all viewing angles, the black luminance is poor, and yellow and blue may be simultaneously viewed. If the biaxial degree exceeds 0.6, the light transmittance in the black state increases at all viewing angles, the black luminance is poor, and yellow and blue may be simultaneously viewed. For example, the biaxial degree may be 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, for example, 0.4 to 0.6, and the effect is significantly remarkable within this range.

[0048] According to one embodiment, the retardation film may have a value of 0.8 to 1.2 in the following formula 1 and a value of 0.9 to 1.1 in the following formula 2. When the retardation film is manufactured with the composition for retardation film described below within the range of the values ​​of formula 1 and formula 2, it is easy to provide the effect of improving visibility at all viewing angles and reducing the light transmittance in the black state at all viewing angles. For example, the value of formula 1 may be 0.8, 0.85, 0.9, 0.95, 1.0, 1.05, 1.1, for example, 0.9 to 1.1, and the value of formula 2 may be 0.9, 0.95, 1.0, 1.05, 1.1, for example, 0.95 to 1.05. [Formula 1] Re(450nm) / Re(550nm) [Formula 2] Re(650nm) / Re(550nm) In formulas 1 and 2, Re(450 nm), Re(550 nm), and Re(650 nm) are the in-plane retardations (unit: nm) of the retardation film at wavelengths of 450 nm, 550 nm, and 650 nm, respectively.

[0049] According to one embodiment, the retardation film has an in-plane retardation at a wavelength of 450 to 650 nm of 176 to 360 nm, for example, 176 nm, 180 nm, 185 nm, 190 nm, 195 nm, 200 nm, 205 nm, 210 nm, 215 nm, 220 nm, 225 nm, 230 nm, 235 nm, 240 nm, 245 nm, 250 nm, 255 nm, 260 nm, 265 nm, 270 nm, 275 nm, 280 nm, 285 nm, 290 nm, 295 nm, 300 nm, 305 nm, 310 nm, 315 nm, 320 nm, 325 nm, 330 nm, 335 nm, 340 nm, 345 nm, 350 nm, 355 nm, 360 nm, for example, 225 to 308 nm. In this range, the values ​​of the above-mentioned formula 1 and formula 2 can be easily reached, and the effect of lowering the light transmittance in the black state over the entire viewing angle can be provided.

[0050] According to one embodiment, the retardation film may have an in-plane retardation of 220 to 300 nm at a wavelength of 550 nm, and a degree of biaxiality of 0.2 to 0.6. In this range, the effect of reducing the light transmittance in the black state at all viewing angles can be easily provided. Preferably, the retardation film may have an in-plane retardation of 220 nm, 225 nm, 230 nm, 235 nm, 240 nm, 245 nm, 250 nm, 255 nm, 260 nm, 265 nm, 270 nm, 275 nm, 280 nm, 285 nm, 290 nm, 295 nm, 300 nm, for example, 250 to 280 nm at a wavelength of 550 nm, and may have a degree of biaxiality of 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, for example, 0.4 to 0.6. Within this range, the light transmittance can be significantly reduced to 0.3% or less.

[0051] FIG. 3 shows the degree of biaxiality (NZ) at a wavelength of 550 nm and the light transmittance value (Y-axis, unit: %) of the retardation film when a polarizing plate according to one embodiment is mounted on a horizontal electric field type, for example, an IPS liquid crystal panel, and driven. The degree of biaxiality (NZ) at a wavelength of 550 nm and the light transmittance value (Y-axis, unit: %) of the in-plane retardation at a wavelength of 550 nm (X-axis, unit: nm) are shown.

[0052] In FIG. 3, ■ indicates the light transmittance when the retardation film has an NZ of 0.4 at a wavelength of 550 nm, ● indicates the light transmittance when the retardation film has an NZ of 0.5 at a wavelength of 550 nm, and ▲ indicates the light transmittance when the retardation film has an NZ of 0.6 at a wavelength of 550 nm.

[0053] Referring to FIG. 3, it can be seen that when the in-plane retardation of the retardation film at a wavelength of 550 nm is 250 to 280 nm and the degree of biaxiality is 0.4 to 0.6, the light transmittance is significantly reduced to 0.3% or less.

[0054] The retardation film may be formed from a composition for a retardation film.

[0055] The composition for retardation film may include a resin and one or more of the compounds represented by the following chemical formulas I to IV. The composition for retardation film is easy to achieve the above-mentioned optical properties.

[0056] The resin is a cellulose ester resin, and the resin is contained as a main component in the retardation film. Here, the term "main component" means that the resin is contained in an amount of 70% by weight or more, for example, 75 to 99% by weight, or 80 to 99% by weight, based on the solid content of the retardation film or the composition for the retardation film.

[0057] The cellulose ester resin has a plurality of aromatic -CO- groups as a substituent, a plurality of primary unsaturated or saturated (C 1-6 ) alkyl-CO- groups, and a cellulose ester resin regioselectively substituted with a plurality of hydroxy groups as substituents.

[0058] Here, “aromatic —CO—” means (i) an aryl group that is unsubstituted or has 1 to 5 R 1 Replaced by (C 6-20 ) aryl-CO-, or (ii) heteroaryl is a 5-10 membered ring having 1 to 4 heteroatoms selected from N, O and S, and heteroaryl is unsubstituted or has 1 to 5 R 1 R may be heteroaryl-CO- substituted by 1 follows the definition explained below.

[0059] According to one embodiment, the regioselectively substituted cellulose ester based resin can include multiple alkyl-acyl or alkyl-CO- groups, multiple aryl-acyl or aryl-CO- groups, multiple heteroaryl-acyl or heteroaryl-CO- groups.

[0060] An acyl substituent or R-CO- refers to a substituent having the structure: [ka]

[0061] Such acyl or R-CO- groups in cellulose esters are generally attached to the pyranose ring of cellulose through an ester bond (ie, through an oxygen atom).

[0062] Aromatic -CO- may be an acyl substituent having an aromatic-containing ring system. Examples of this may include aryl-CO- or heteroaryl-CO-. Specific examples include benzoyl, naphthoyl and furoyl, each of which may be unsubstituted or substituted.

[0063] The term "aryl-acyl" substituent refers to an acyl substituent in which "R" is an aryl group. The term "aryl" refers to a monovalent group formed by removing a hydrogen atom from a ring carbon of an arene (i.e., a monocyclic or polycyclic aromatic hydrocarbon). In some cases, the aryl-acyl group is located before a carbon unit. For example, (C 5-6 ) aryl-acyl, (C 6-12 ) aryl-acyl, or (C 6-20 ) Aryl-acyl. Examples of aryl groups suitable for use in the various embodiments include, but are not limited to, phenyl, benzyl, tolyl, xylyl, and naphthyl groups. Such aryl groups may be substituted or unsubstituted.

[0064] The term "alkyl-acyl" refers to an acyl substituent where "R" is an alkyl group. "Alkyl" means a monovalent group formed by removing a hydrogen atom from a non-aromatic hydrocarbon and may contain heteroatoms. Alkyl groups suitable for use in the present invention may be linear, branched or cyclic, and may be saturated or unsaturated. Alkyl groups suitable for use in the present invention include any (C 1-20 ), (C 1-12 ), (C 1-5 ), or (C 1-3 ) alkyl groups. In various embodiments, alkyl is C 1-5 In yet another embodiment, the alkyl group is a straight chain alkyl group. 1-3It may be a straight chain alkyl group. Specific examples of suitable alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, octyl, decyl, dodecyl, cyclopentyl, and cyclohexyl groups. Examples of alkyl-acyl groups include acetyl, propionyl, and butyroyl groups.

[0065] The term "haloalkyl" refers to an alkyl substituent in which one or more hydrogens are replaced by halogen atoms. The carbon units of a haloalkyl group, e.g., halo(C 1-6 ) alkyl is often included. Haloalkyl groups may be straight or branched. Non-limiting examples of haloalkyl groups include chloromethyl, trifluoromethyl, dibromoethyl, and the like.

[0066] The term "heteroalkyl" means an alkyl in which one or more carbon atoms have been replaced with a heteroatom such as, for example, N, O and S.

[0067] The term "heteroaryl" refers to an aryl in which one or more of the carbon units of the aryl ring are replaced by a heteroatom such as O, N, and S. The heteroaryl ring may be monocyclic or polycyclic. Often, the units that make up the heteroaryl ring system include, for example, 5- to 20-membered ring systems. A 5-membered heteroaryl refers to a ring system having 5 atoms that form the heteroaryl ring. Non-limiting examples of heteroaryl include pyridinyl, quinolinyl, pyrimidinyl, and thiophenyl, and the like.

[0068] The term "alkoxy" refers to an alkyl-O- or alkyl group terminally attached to an oxygen atom. Often, the term refers to a carbon unit, e.g., (C 1-6 ) alkoxy. Non-limiting examples of alkoxy include methoxy, ethoxy, and propoxy groups, and the like.

[0069] The term "haloalkoxy" refers to an alkoxy in which one or more of the hydrogens are replaced with a halogen. Often, the carbon unit, e.g., halo(C 1-6 Non-limiting examples of haloalkoxy include trifluoromethoxy, bromomethoxy, and 1-bromoethoxy groups, and the like.

[0070] The term "halo" means halogens such as fluoro, chloro, bromo or iodine.

[0071] The term "degree of substitution (DS)" is used to describe the level of substitution of the substituents on anhydroglucose units ("AGU"). Generally, existing cellulose contains three hydroxyl groups that can be substituted on each AGU. Thus, DS can have a value of 0 to 3. However, low molecular weight cellulose mixed esters can have a total degree of substitution slightly higher than 3 due to end group contribution. Since DS is a statistical average, not all AGUs have a single substituent, with a value of 1. In some cases, there may be unsubstituted anhydroglucose units, some with two and some with three substituents, and more often the value is not an integer. The total DS is defined as the average number of all substituents per anhydroglucose unit. The degree of substitution per AGU can also refer to a specific substituent, such as, for example, a hydroxyl group, an acetyl group, a butyryl group, or a propionyl group. The degree of substitution can also be specified by the carbon units of the anhydroglucose unit.

[0072] When the degree of substitution refers to the hydroxy group (i.e., DS OH ), the designation referring to the average hydroxyl group per unsubstituted anhydroglucose. OH is not used in calculating the total degree of substitution.

[0073] Regioselectivity can be measured by determining the relative degree of substitution ("RDS") at C6, C3 and C2 of the cellulose ester by carbon-13 NMR spectroscopy (Macromolecules, 1991, 24, 3050-3059). In the case of one type of acyl substituent, or when a second acyl substituent is present in small amounts (DS<0.2), the RDS can be most easily measured directly by cycloalkane integration. When two or more acyl substituents are present in similar amounts, in addition to determining the ring RDS, the cellulose ester may have to be fully substituted with additional substituents to independently measure the RDS of each substituent by integration of the carbonyl carbon. Regioselectivity is generally not observed in existing cellulose esters, and the C6 / C3, C6 / C2 or C3 / C2 RDS ratios are generally close to 1 or less. Essentially, existing cellulose esters are random copolymers. In contrast, when one or more acylating reagents are added to cellulose dissolved in an appropriate solvent, the C6 position of cellulose is acylated much faster than the C2 and C3 positions. As a result, the C6 / C3 and C6 / C2 ratios are much greater than 1, which is characteristic of 6,3 or 6,2 enhanced regioselectively substituted cellulose esters.

[0074] According to one embodiment, the cellulose ester comprises a structure generally represented by the following structural formula: [ka] In the above structural formula, R 2 , R 3 , and R 6 are each independently hydrogen (except R 2 , R 3 and R 6 is not simultaneously hydrogen), an alkyl-acyl group or an aryl-acyl group bonded to cellulose through an ester bond, and n is an integer equal to or greater than 1.

[0075] The degree of polymerization ("DP") of the cellulose esters produced by these methods may be 10 or more, 50 or more, 100 or more, or 250 or more.

[0076] The acylating reagent may include, but is not limited to, alkyl or aryl carboxylic anhydrides, carboxylic acid halides, and / or carboxylic acid esters containing the alkyl or aryl groups described above suitable for use in the acyl substituents of the regioselectively substituted cellulose esters described herein. Examples of suitable carboxylic acid anhydrides include, but are not limited to, acetic anhydride, propionic anhydride, butyric anhydride, pivaloyl anhydride, benzoic anhydride, and naphthoyl anhydride. Examples of carboxylic acid halides include, but are not limited to, acetyl, propionyl, butyryl, pivaloyl, benzoyl, and naphthoyl chlorides or bromides. Examples of carboxylic acid esters include, but are not limited to, acetyl, propionyl, butyryl, pivaloyl, benzoyl, and naphthoyl methyl esters. In one or more embodiments, the acylating agent may be one or more carboxylic acid anhydrides selected from the group consisting of acetic anhydride, propionic anhydride, butyric anhydride, pivaloyl anhydride, benzoyl anhydride, and naphthoyl anhydride.

[0077] The cellulose ester resin has a plurality of aromatic -CO- groups as a substituent, a plurality of primary unsaturated or saturated (C 1-6 ) alkyl-CO- groups, and a cellulose ester resin regioselectively substituted with a plurality of hydroxy groups as substituents.

[0078] According to one embodiment, the cellulose ester resin may have a hydroxy substitution degree of 0.2 to 2.0, a substitution degree at C2 of 0.15 to 0.8, a substitution degree at C3 of 0.05 to 0.6, a substitution degree at C6 of 0.05 to 0.6, and a total substitution degree of 0.25 to 2.5.

[0079] According to an embodiment, the cellulose ester resin may have a hydroxy substitution degree of 0.2 to 2.0, a substitution degree at C2 by an aromatic-CO group or an alkyl-CO group of 0.15 to 0.8, a substitution degree at C3 by an aromatic-CO group or an alkyl-CO group of 0.05 to 0.6, a substitution degree at C6 by an aromatic-CO group or an alkyl-CO group of 0.05 to 0.6, and a total substitution degree by an aromatic-CO group or an alkyl-CO group of 0.25 to 2.5.

[0080] The cellulose ester resin is a primary unsaturated or saturated (C 1-6 In one embodiment, the cellulose ester resin has a degree of substitution of primary unsaturated or saturated (C 1-6 ) alkyl-acyl substituents.

[0081] In some such embodiments, the first unsaturated or saturated (C 1-20 ) alkyl-CO-substituent is acetyl, propionyl, butyryl, isobutyryl, 3-methylbutanoyl, pentanoyl, 4-methylpentanoyl, 3-methylpentanoyl, 2-methylpentanoyl, hexanoyl or crotonyl. In some of these embodiments, the first unsaturated or saturated (C 1-6 ) The alkyl-CO-substituent is acetyl, propionyl or crotonyl.

[0082] In one embodiment, or in combination with any other embodiment, the cellulose ester resin comprises a plurality of second (C 1-20 In some such embodiments, the second (C 1-20 ) alkyl-CO-substituent ("DS SAk ") has a degree of substitution of 0.05 to 0.6.

[0083] In some of such embodiments, the second (C 1-20) alkyl-CO-substituent is acetyl, propionyl, butyryl, isobutyryl, 3-methylbutanoyl, pentanoyl, 4-methylpentanoyl, 3-methylpentanoyl, 2-methylpentanoyl, hexanoyl, pivalyl, or 2-ethylhexanoyl. In some such embodiments, the second (C 1-20 ) alkyl-CO-substituent is acetyl, isobutyryl, 3-methylbutanoyl, pentanoyl, 4-methylpentanoyl, 3-methylpentanoyl, 2-methylpentanoyl, hexanoyl, or 2-ethylhexanoyl. In some such embodiments, the second (C 1-20 ) The alkyl-CO-substituent is acetyl or 2-ethylhexanoyl.

[0084] In one embodiment, or in combination with any other embodiment, the aromatic -CO- is (C 6-20 ) aryl-CO-, wherein the aryl is unsubstituted or has 1 to 5 R 1 In some such embodiments, the aromatic -CO- is benzoyl or naphthoyl, which is unsubstituted or substituted with 1 to 5 R 1 In some such embodiments, the aromatic -CO- is unsubstituted or substituted with 1 to 5 R 1 In some of these embodiments, the aromatic -CO- is unsubstituted or substituted with 1 to 5 R 1 is naphthoyl substituted by

[0085] In one embodiment, or in combination with any other embodiment, the aromatic -CO- is unsubstituted or R 1 In some such embodiments, the cellulose ester has a total DS of 0.40 to 1.20. ArCO In one subsection of such an embodiment, the C3DS ArCO and C3DS ArCO The sum is 0.30 to 0.75.

[0086] In one embodiment, or in combination with any other embodiment, the aromatic -CO- is unsubstituted or has 1 to 5 R 1 In some such embodiments, the cellulose ester has a total DS of 0.30 to 0.6. ArCO In one subsection of such an embodiment, the C3DS ArCO and C3DS ArCO The sum of is 0.20 to 0.40. In one subsection of this embodiment, C3DS ArCO and C3DS ArCO The sum is 0.30 to 0.40.

[0087] In one embodiment, or in combination with any other embodiment, aromatic -CO- is heteroaryl-CO-, where heteroaryl is a 5-10 membered ring having 1- to 4-heteroatoms selected from N, O and S, where heteroaryl is unsubstituted or has 1-5 R 1 In some such embodiments, heteroaryl-CO- is pyridinyl-CO-, pyrimidinyl-CO-, furanyl-CO-, or pyrrolyl-CO-. In some such embodiments, heteroaryl-CO- is 2-furoyl.

[0088] In one embodiment, or in combination with any other embodiment, the cellulose ester has a totDS of 0.4 to 1.6. ArCO In one embodiment, or in combination with any other embodiment, the cellulose ester has a totDS of 1.0 to 1.6. ArCO In one embodiment, or in combination with any other embodiment, the cellulose ester has a totDS of 0.3 to 1.25. ArCO In one embodiment, or in combination with any other embodiment, the cellulose ester has a totDS of 0.4 to 1.2. ArCO In one embodiment, or in combination with any other embodiment, the cellulose ester has a totDS of 0.4 to 0.8. ArCOIn one embodiment, or in combination with any other embodiment, the cellulose ester has a totDS of 0.3 to 0.8. ArCO In one embodiment, or in combination with any other embodiment, the cellulose ester has a totDS of 0.3 to 0.6. ArCO In one embodiment, or in combination with any other embodiment, the cellulose ester has a totDS of 0.2 to 0.6. ArCO In one embodiment, or in combination with any other embodiment, the cellulose ester has a totDS of 0.2 to 0.5. ArCO In one embodiment, or in combination with any other embodiment, the cellulose ester has a totDS of 0.8 to 1.2. ArCO In one embodiment, or in combination with any other embodiment, the cellulose ester has a totDS of 0.5 to 1.1. ArCO has.

[0089] In one embodiment, or in combination with any other embodiment, DS OH In one embodiment, or in combination with any other embodiment, DS OH In one embodiment, or in combination with any other embodiment, DS OH In one embodiment, or in combination with any other embodiment, DS OH In one embodiment, or in combination with any other embodiment, DS OH In one embodiment, or in combination with any other embodiment, DS OH In one embodiment, or in combination with any other embodiment, DS OH is 0.5 to 0.8.

[0090] In one embodiment, or in combination with any other embodiment, C2DS ArCO and C3DS ArCO The sum of is 0.3 to 1.25. In one embodiment, or in combination with any other embodiment, C2DS ArCO and C3DSArCO The sum of is 0.2 to 0.4. In one embodiment, or in combination with any other embodiment, C2DS ArCO and C3DS ArCO The sum of is 0.3 to 0.4. In one embodiment, or in combination with any other embodiment, C2DS ArCO and C3DS ArCO The sum of is 0.4 to 1.2. In one embodiment, or in combination with any other embodiment, C2DS ArCO and C3DS ArCO The sum of is 0.4 to 1.1. In one embodiment, or in combination with any other embodiment, C2DS ArCO and C3DS ArCO The sum of is 0.4 to 1.0. In one embodiment, or in combination with any other embodiment, C2DS ArCO and C3DS ArCO The sum of is 0.5 to 1.1. In one embodiment, or in combination with any other embodiment, C2DS ArCO and C3DS ArCO The sum of is 0.6 to 1.0. In one embodiment, or in combination with any other embodiment, C2DS ArCO and C3DS ArCO The sum of is 0.6 to 1.25. In one embodiment, or in combination with any other embodiment, C2DS ArCO and C3DS ArCO The sum is 0.30 to 0.75.

[0091] The composition for a retardation film, that is, the retardation film, may contain one or more components A of the chemical formulae I to IV. [Chemical formula I] [ka] [Chemical formula II] [ka] [Chemical formula III] [ka] [Chemical formula IV] [ka] In the above chemical formulas I to IV, Ring A is (C 6-20 ) aryl or a 5-10 membered heteroaryl containing 1-4 heteroatoms selected from N, O and S; Ring B is (C 6-20 ) aryl or a 5-10 membered heteroaryl containing 1-4 heteroatoms selected from N, O and S; Ring C is (C 6-20 ) aryl or a 5-10 membered heteroaryl containing 1-4 heteroatoms selected from N, O and S; R 1 is saturated or unsaturated (C 1-20 ) alkyl; saturated or unsaturated halo(C 1-20 ) alkyl; optionally 1 to 5 substituted with alkyl, haloalkyl, alkoxy, haloalkoxy or halo (C 6-20 ) aryl; 5-10 membered heteroaryl containing 1-4 heteroatoms selected from N, O and S; or -CH2C(O)-R 3 and R 2 are independently hydrogen, saturated or unsaturated (C 1-20 ) alkyl, or saturated or unsaturated halo(C 1-20 ) alkyl, R 3 is saturated or unsaturated (C 1-20 ) alkyl, saturated or unsaturated halo(C 1-20 )Alkyl(C 6-20 ) aryl, or a 5-10 membered heteroaryl containing 1-4 heteroatoms selected from N, O and S, wherein the aryl or the heteroaryl is unsubstituted or has 1-5 R 6 is replaced by R 4 is saturated or unsaturated (C 1-20 ) alkyl, saturated or unsaturated halo(C1-20 ) alkyl, or saturated or unsaturated (C 1-20 )Alkyl-CO-(C 1-20 ) alkyl, where each group is unsubstituted or has 1 to 3 hydroxy groups, saturated or unsaturated (C 1-20 ) alkyl, saturated or unsaturated halo(C 1-20 ) alkyl, saturated or unsaturated (C 1-20 ) alkoxy, saturated or unsaturated halo(C 1-20 ) alkoxy, saturated or unsaturated hydroxy (C 1-20 ) alkyl, saturated or unsaturated (C 1-20 )Alkoxy-(C 1-20 ) alkyl, saturated or unsaturated (C 1-20 )Alkoxy-hydroxy(C 1-20 ) alkyl, saturated or unsaturated (C 1-20 )Alkoxy-(C 1-20 )Alkyl-CO-(C 1-20 ) alkyl, saturated or unsaturated (C 1-20 ) Alkyl-CO, saturated or unsaturated (C 1-20 ) Alkyl-COO, saturated or unsaturated (C 1-20 )Alkyl-O-CO-(C 1-20 ) alkyl, saturated or unsaturated (C 1-20 )Alkyl-COO-(C 1-20 ) alkyl, saturated or unsaturated (C 1-20 )Alkoxy-(C 1-20 )Alkyl-COO-(C 1-20 ) alkyl, or (C 1-20 )Alkoxy-(C 1-20 )Alkyl-O-CO-(C 1-20 ) substituted by alkyl; Each R 5 are independently hydroxy, cyano, saturated or unsaturated (C 1-20 ) alkyl, saturated or unsaturated halo(C 1-20 ) alkyl, saturated or unsaturated (C 1-20 ) alkoxy, saturated or unsaturated halo(C 1-20 ) alkoxy, or halo; Each R 6are independently hydroxy, cyano, saturated or unsaturated (C 1-20 ) alkyl, saturated or unsaturated halo(C 1-20 ) alkyl, saturated or unsaturated (C 1-20 ) alkoxy, saturated or unsaturated halo(C 1-20 ) alkoxy, or halo or (C 6-20 ) aryl, wherein the aryl is unsubstituted or has 1 to 5 R 7 is replaced by Each R 7 are independently hydroxy, saturated or unsaturated (C 1-6 ) alkyl, saturated or unsaturated halo(C 1-6 ) alkyl, or saturated or unsaturated (C 1-6 ) alkoxyl, R 8 is saturated or unsaturated (C 1-20 ) alkyl, saturated or unsaturated halo(C 1-20 ) alkyl, saturated or unsaturated (C 1-20 ) alkoxyl, or saturated or unsaturated halo(C 1-20 ) alkoxyl, Each R 9 is R 4 -O-, hydroxy, saturated or unsaturated (C 1-20 ) alkyl, saturated or unsaturated hetero (C 1-20 ) alkyl, saturated or unsaturated halo(C 1-20 ) alkyl, saturated or unsaturated (C 1-20 )Alkyl-CO-(C 1-20 ) alkyl-, saturated or unsaturated (C 1-20 )Alkyl-COO-(C 1-20 ) alkyl-, saturated or unsaturated (C 1-20 ) alkyl-COO-, saturated or unsaturated (C 1-20 ) alkyl-O-CO-, saturated or unsaturated (C 1-20 ) alkyl-CO-, saturated or unsaturated (C 1-20 )Alkoxy-(C 1-20 )Alkyl-CO-O-(C 1-20 ) alkyl, saturated or unsaturated (C1-20 )Alkoxy-(C 1-20 )Alkyl-O-CO-(C 1-20 ) alkyl, saturated or unsaturated (C 1-20 )Alkoxy-(C 1-20 )Alkyl-COO-(C 1-20 ) alkyl, (C 1-20 )Alkoxy-(C 1-20 )Alkyl-O-CO-(C 1-20 ) alkyl-(C6-10)aryl, 5-10 membered heteroaryl containing 1-4 heteroatoms selected from N, O and S; In this case, each group is unsubstituted or has 1 to 3 hydroxy groups, saturated or unsaturated (C 1-20 ) alkyl, saturated or unsaturated halo(C 1-20 ) alkyl, saturated or unsaturated (C 1-20 ) alkoxyl, saturated or unsaturated halo(C 1-20 ) alkoxyl, saturated or unsaturated hydroxy (C 1-20 ) alkyl, saturated or unsaturated (C 1-20 )Alkoxy-(C 1-20 ) alkyl, saturated or unsaturated (C 1-20 )Alkoxy-hydroxy(C 1-20 ) alkyl or saturated or unsaturated (C 1-20 )Alkoxy-(C 1-20 )Alkyl-CO-(C 1-20 ) alkyl-, saturated or unsaturated (C 1-20 ) Alkyl-CO, saturated or unsaturated (C 1-20 ) Alkyl-COO, saturated or unsaturated (C 1-20 )Alkyl-O-CO-(C 1-20 ) alkyl, saturated or unsaturated (C 1-20 )Alkyl-COO-(C 1-20 ) alkyl, saturated or unsaturated (C 1-20 )Alkoxy-(C 1-20 )Alkyl-COO-(C 1-20 ) alkyl, or (C 1-20 )Alkoxy-(C 1-20 )Alkyl-O-CO-(C 1-20 ) substituted by alkyl; each n is 0, 1, 2, 3, 4, or 5; each m is 0, 1, 2, 3, or 4; k is 0, 1, 3 or 4.

[0092] According to one embodiment, component A is selected from the group consisting of 1,3-diphenyl-1,3-propanedione, avobenzone, (2-hydroxy-4-(octyloxy)phenyl(phenyl)methanone, (2-hydroxy-4-methoxyphenyl)(2-hydroxyphenyl)methanone, 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-(hexyloxy)phenol (Tinuvin (Tinuvin) 1577), 2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl]-5-[2-hydroxy-3-(dodecyloxy- and tridecyloxy)propoxy]phenol (Tinuvin 400), isopropyl alcohol, ethyl ... octyl 2-(4-(4,6-di([1,1'-biphenyl]-4-yl)-1,3,5-triazin-2-yl)-3-hydroxyphenoxy)propanoate (Tinuvin 479), 6,6'-(6-(2,4-dibutoxyphenyl)-1,3,5-triazine-2,4-diyl)bis(3-butoxyphenol) (Tinuvin 460), 2-(4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl)-5-(3-((2-ethylhexyl)oxy)-2-hydroxypropoxy)phenol (Tinuvin 405), 7-diethylamino-4-methylcoumarin, or combinations thereof.

[0093] According to one embodiment, component A may be present in an amount of 1% by weight or more. In some of these embodiments, component A may be present in a range of 1 to 30% by weight. In some of these embodiments, component A may be present in a range of 1 to 20% by weight. In some of these embodiments, component A may be present in a range of 1 to 15% by weight. Within these ranges, the effects of the present invention can be easily achieved.

[0094] The composition for retardation film may further contain a plasticizer to improve the workability and flexibility of the retardation film. The plasticizer may be contained in an amount of 0.1 to 10 wt %, for example 0.1 to 5 wt %, based on the solid content of the retardation film or the composition for retardation film. In this range, the glass transition temperature and melting temperature of the material from which the retardation film is formed can be lowered, and lower temperature and / or simplified film production can be made possible.

[0095] The plasticizer can be selected from phosphate-based plasticizers, phthalate-based plasticizers, terephthalate-based plasticizers, trimellitate-based plasticizers, benzoate-based plasticizers, glycolate-based plasticizers, citrate ester-based plasticizers, polyhydric alcohol ester-based plasticizers, polyol-based plasticizers, polyether-based plasticizers, and the like.

[0096] Non-limiting examples of glycolate plasticizers can include methylphthalyl methyl glycolate, ethylphthalyl ethyl glycolate, propylphthalyl propyl glycolate, butylphthalyl butyl glycolate, octylphthalyl octyl glycolate, methylphthalyl ethyl glycolate, ethylphthalyl methyl glycolate, ethylphthalyl propyl glycolate, methylphthalyl butyl glycolate, ethylphthalyl butyl glycolate, butylphthalyl methyl glycolate, butylphthalyl ethyl glycolate, butylphthalyl ethyl glycolate, propylphthalyl butyl glycolate, butylphthalyl propyl glycolate, methylphthalyl octyl glycolate, ethylphthalyl octyl glycolate, octylphthalyl methyl glycolate, and octylphthalyl ethyl glycolate.

[0097] The retardation film can be produced by solution casting and stretching the composition for retardation film. According to one embodiment, the retardation film can be produced by adding a solvent to the composition for retardation film itself or the composition for retardation film to produce a casting solution, applying the casting solution to a substrate and drying it to produce an unstretched film, and stretching the unstretched film in the transverse direction (TD) of the unstretched film.

[0098] In one embodiment, the orientation direction of the main chain of the resin contained in the retardation film may be adjusted by the viscosity of the composition for the retardation film, the concentration of the resin in the composition for the retardation film, and the stretching direction and stretching ratio of the unstretched film when producing the unstretched film.

[0099] In one embodiment, the slow axis of the retardation film is −5° to +5° relative to the light absorption axis of the polarizer, for example, −3° to +3°, or may be 0°. Within this range, the effects of the present invention may be easily achieved.

[0100] In one embodiment, the slow axis of the retarder film may be substantially parallel to the mechanical direction of the retarder film.

[0101] The polarizer can convert incident natural light or polarized light into linearly polarized light in a specific direction. The polarizer may have a thickness of 2 to 30 μm, specifically 4 to 25 μm, and within this range, it can be used in a polarizing plate.

[0102] The polarizer can be manufactured from a film mainly composed of a polyvinyl alcohol-based resin by a conventional method known to those skilled in the art. For example, the polarizer may be manufactured by iodine dyeing and stretching. The polarizer has a light absorption axis and a light transmission axis perpendicular to the light absorption axis in the in-plane direction, and the light absorption axis may be MD and the light transmission axis may be TD.

[0103] The polarizing plate may further include one or more top protective layers on the top surface of the polarizer.

[0104] The upper protective layer may include at least one of an optically transparent protective coating layer and a protective film. The protective coating layer may include a coating layer formed of a composition including an active energy ray curable compound. The protective film may be an optically transparent film, and may be a film made of at least one resin selected from the group consisting of cellulose-based films including triacetyl cellulose (TAC) and the like, polyester-based films including polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, and the like, cyclic polyolefin-based films, polycarbonate-based films, polyethersulfone-based films, polysulfone-based films, polyamide-based films, polyimide-based films, polyolefin-based films, polyarylate-based films, polyvinyl alcohol-based films, polyvinyl chloride-based films, and polyvinylidene chloride-based films. Specifically, TAC and PET films may be used.

[0105] The upper protective layer may have a thickness of 0.1 to 100 μm, specifically 5 to 70 μm, specifically 15 to 45 μm, and this range can be used for the polarizing plate.

[0106] The upper protective layer may be attached to the adherend by an adhesive layer. If the function of the polarizing plate is not affected even if the upper protective layer is omitted, the upper protective layer may be omitted.

[0107] The polarizing plate may further include an adhesive layer on the bottom surface thereof. The adhesive layer serves to adhere the polarizing plate to the panel. The adhesive layer may be formed of a conventional adhesive composition known to those skilled in the art.

[0108] Referring to FIG. 1, the polarizing plate may include a polarizer 100 , an upper protective layer 300 laminated on an upper surface of the polarizer 100 , and a retardation film 200 laminated on a lower surface of the polarizer 100 .

[0109] Referring to FIG. 2, the polarizing plate may include a polarizer 100, an upper protective layer 300 laminated on an upper surface of the polarizer 100, and a retardation film 200 and a lower protective layer 400 sequentially laminated on a lower surface of the polarizer 100.

[0110] optical display device According to an embodiment, an optical display device includes the polarizer. The optical display device may include a liquid crystal display device. The polarizer may be included as a viewing side polarizer in the optical display device. In an embodiment, the liquid crystal display device is a horizontal alignment mode liquid crystal, and may be an IPS (in-plane switching), FFS (fringe-field switching), ADS (advanced super dimension switching) or PLS mode liquid crystal display device.

[0111] According to one embodiment, the liquid crystal display device may include a liquid crystal panel, a viewer-side polarizing plate on one side of the liquid crystal panel, and a light source-side polarizing plate on the other side of the liquid crystal panel. The light absorption axis of the polarizer in the viewer-side polarizing plate may be substantially perpendicular to the light absorption axis in the light source-side polarizing plate. When the light absorption axis of the polarizer in the viewer-side polarizing plate is set to 0°, the light absorption axis in the light source-side polarizing plate may be 90°, and the rubbing direction of the liquid crystal in the liquid crystal panel may be 90°. The viewer-side polarizing plate may include the polarizing plate according to the embodiment described above. EXAMPLES

[0112] The present invention will be described in more detail with reference to the following preferred embodiments, which are merely examples of the present invention and should not be construed as limiting the present invention in any way.

[0113] Example 1 A composition for retardation film (EASTMAN Chemical Ltd.) containing a regioselectively substituted cellulose ester resin (propionyl group C2 propionyl group substitution degree 0.26, propionyl group substitution degree C3 0.34, propionyl group substitution degree C6 0.53, total propionyl group substitution degree 2.33, hydroxy substitution degree 1.87) was used to produce an unstretched film by a solution casting method. The unstretched film produced was stretched in the width direction of the unstretched film at a stretch ratio of 1.5 times to produce a retardation film (wavelength 550 nm, in-plane retardation 270 nm, degree of biaxiality 0.4, thickness: 56 μm, nx = 1.5323, ny = 1.5275, nz = 1.5304).

[0114] A polyvinyl alcohol film (TS#20, Kuraray, Japan, thickness before stretching: 20 μm) was stretched 6 times in MD uniaxially in an iodine solution at 55° C. to produce a polarizer with a light transmittance of 45%.

[0115] A polyethylene terephthalate (PET) film with an anti-reflection layer formed on the upper surface of the manufactured polarizer was laminated, and the manufactured retardation film was laminated on the lower surface of the polarizer to manufacture a polarizing plate. In the manufactured polarizing plate, the angle between the light transmission axis of the polarizer (width direction of the polarizer) and the main chain direction of the site-selectively substituted cellulose ester resin in the retardation film is 0°.

[0116] Examples 2 to 6 A polarizing plate was prepared in the same manner as in Example 1, except that a regioselectively substituted cellulose ester resin having a different substitution degree was used and the stretch ratio was changed.

[0117] Comparative Example 1 to Comparative Example 4 Polarizing plates were produced in the same manner as in Example 1, except that the in-plane retardation and / or the degree of biaxiality of the retardation film was changed and the stretching ratio was changed.

[0118] The polarizing plates of the examples and comparative examples were evaluated for the following physical properties, and the results are shown in Table 1 below and in FIGS. (1) Optical properties of retardation film: The retardation film was measured using AXOSCAN. (2) Angle: The angle between the light transmission axis of the polarizer in the polarizing plate and the main chain direction of the cellulose ester resin in the retardation film was measured by AXOSCAN when the retardation film and the polarizer were separated, and the main chain direction of the cellulose ester resin was measured by X-ray diffraction (X-RD) method, and the relative angle between them was calculated. (3) Maximum light transmittance (unit: %): The polarizers manufactured in the examples and comparative examples were installed instead of the polarizer on the viewing side of a Samsung Electronics TV model equipped with an IPS LCD panel and driven. The maximum light transmittance in the black state was calculated at all viewing angles using the Extended Jones Matrix method through a TECHWIZ 1D (SANAI SYSTEM, KOREA) simulation program. However, the reduction in light transmittance due to the color filter inside the panel was excluded from the above calculation. The lower the maximum light transmittance, the more light leakage can be prevented and the greater the visibility can be. (4) Black Visibility and Color: A Samsung Electronics TV model equipped with an IPS LCD panel was driven with the polarizers manufactured in the examples and comparative examples installed instead of the polarizer on the viewing side. The black visibility and color were evaluated by visual evaluation.

[0119] [Table 1] *The retardation films of the examples and comparative examples satisfy nx>nz>ny at a wavelength of 550 nm.

[0120] As shown in Table 1, the polarizing plate of the present invention, which includes a single-layer retardation film, was able to provide the effects of improving visibility at all viewing angles, minimizing color change, and reducing the maximum light transmittance in the black state at all viewing angles to improve light leakage. On the other hand, as shown in Table 1, the polarizing plate of the comparative example, which includes a retardation film that does not satisfy the optical characteristics of the present invention, had lower effects than the examples.

[0121] As shown in Figures 4 and 5, the polarizing plate of Example 1 had excellent black luminance and minimized color change over the entire viewing angle. On the other hand, as shown in Figures 6 to 9, the polarizing plates of Comparative Examples 2 and 3 had poor black luminance compared to Example 1 and exhibited significant color change over the entire viewing angle.

[0122] Simple modifications or alterations of the present invention may be easily implemented by a person having ordinary skill in the art, and all such modifications or alterations are deemed to be included within the scope of the present invention.

Claims

1. Polarizers, and A retardation layer laminated on one surface of the polarizer Including, The retardation layer includes a retardation film having nx>nz>ny at a wavelength of 550 nm (nx, ny, and nz are the refractive indexes in the slow axis direction, the fast axis direction, and the thickness direction of the retardation film at a wavelength of 550 nm), The orientation direction of the main chain of the resin contained in the retardation film is −5° to +5° relative to the light transmission axis of the polarizer, The retardation film is a polarizing plate having a degree of biaxiality of 0.2 to 0.6 at a wavelength of 550 nm.

2. The polarizing plate according to claim 1 , wherein the retardation film is a single-layer retardation film.

3. 2. The polarizing plate according to claim 1, wherein the retardation film has an in-plane retardation of 220 to 300 nm at a wavelength of 550 nm.

4. The polarizing plate according to claim 1, wherein the retardation film has a value of the following formula 1 of 0.8 to 1.2 and a value of the following formula 2 of 0.9 to 1.

1. [Formula 1] Re(450nm) / Re(550nm) [Formula 2] Re(650nm) / Re(550nm) (In the above formulas 1 and 2, Re (450 nm), Re (550 nm), and Re (650 nm) are the in-plane retardations (units: nm) of the retardation film at wavelengths of 450 nm, 550 nm, and 650 nm, respectively.)

5. 2. The polarizing plate according to claim 1, wherein the slow axis of the retardation film is at an angle of −5° to +5° relative to the light absorption axis of the polarizer.

6. The polarizing plate according to claim 1 , wherein the slow axis of the retardation film is parallel to a mechanical direction of the retardation film.

7. The polarizing plate according to claim 1 , wherein the retardation film is a retardation film stretched in a transverse direction (TD).

8. 2. The polarizing plate according to claim 1, wherein nx-ny is 0.0022 to 0.0075, and nx-nz is 0.00044 to 0.0045.

9. 2. The polarizing plate according to claim 1, wherein nx is from 1.500 to 1.710, ny is from 1.480 to 1.700, and nz is from 1.500 to 1.

705.

10. The polarizing plate according to claim 1 , wherein the resin is a main component of the retardation film.

11. The polarizing plate according to claim 1 , wherein the resin is a cellulose ester resin.

12. The cellulose ester resin has a plurality of aromatic —CO— groups as a substituent; a plurality of primary unsaturated or saturated (C １－６ 12. The polarizing plate according to claim 11, comprising a cellulose ester resin regioselectively substituted with a hydroxyl group as a substituent; and a cellulose ester resin regioselectively substituted with a hydroxyl group as a substituent.

13. The cellulose ester resin is The degree of hydroxy substitution is 0.2 to 2.0; The degree of substitution with C2 is 0.15 to 0.8, The degree of substitution with C3 is 0.05 to 0.6, The degree of substitution with C6 is 0.05 to 0.6; The polarizing plate according to claim 12, wherein the total degree of substitution is from 0.25 to 2.

5.

14. The polarizing plate according to claim 1 , wherein the retardation layer is composed of the retardation film alone.

15. 2. The polarizing plate according to claim 1, wherein the retardation film has a thickness of 40 to 100 μm.

16. The polarizing plate according to claim 1 , further comprising a protective layer laminated on another surface of the polarizer.

17. An optical display device comprising the polarizing plate according to any one of claims 1 to 16.

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