Polarizing plate and optical display device

Abstract

Disclosed are a polarizing plate and an optical display device including the same. The polarizing plate includes: a polarizer; and a first protective film stacked on a surface of the polarizer, the first protective film having a total haze of 40% to 60% and an internal haze of 3% to 7%, and the polarizing plate having a light transmittance ratio of 4 or less calculated according to Equation 1 and a light transmittance ratio of 20 or more calculated according to Equation 2.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefits of Korean Patent Application No. 10-2023-0074729 filed in the Korean Intellectual Property Office on June 12, 2023, and all disclosures of the Korean Patent Application are incorporated herein by reference. Technical Field

[0003] Various aspects of embodiments of the present invention relate to a polarizing plate and an optical display device. Background Art

[0004] Due to the reflection of external light, the visibility and contrast of the organic light-emitting device display may be deteriorated. To solve this problem, a polarizing plate may be used to achieve an anti-reflection function by preventing the reflected external light from leaking. It is desirable that the organic light-emitting device display has a small color difference between the front and side surfaces on its screen.

[0005] Recently, light-emitting device displays including organic light-emitting devices, especially televisions (TVs), need not only to display moving images on the screen, but also to enable the TV screen to act as a picture frame for displaying pictures or photos by reproducing pictures or photos on the screen. Usually, such TVs are called frame TVs. The basic requirement of frame TVs is to enable pictures or photos to be clearly viewed. In addition, frame TVs need to reproduce the original texture of pictures or photos (also called "matte texture") so that the pictures or photos appear to be part of the screen rather than floating above the screen.

[0006] The background art of the present invention is disclosed in Japanese Unexamined Patent Publication No. 2006-251659. Summary of the invention

[0007] According to aspects of embodiments of the present invention, there is provided a polarizing plate that can provide a matte texture and reduce a color difference between a front side and a side side on a screen when an image is displayed on the screen.

[0008] An aspect of one or more embodiments of the present invention relates to a polarizing plate.

[0009] According to one or more embodiments, a polarizing plate includes: a polarizer; and a first protective film stacked on a surface of the polarizer, wherein the first protective film has an overall haze of 40% to 60% and an internal haze of 3% to 7%, and the polarizing plate has a light transmittance ratio of 4 or less calculated according to the following equation 1 and a light transmittance ratio of 20 or more calculated according to the following equation 2:

[0010] Transmittance ratio = Tc(430nm) / Tc(550nm), ---(1)

[0011] Transmittance ratio = Tc(700nm) / Tc(550nm), ---(2)

[0012] Wherein Tc(430nm) represents the crossed transmittance of the polarizing plate at a wavelength of 430nm (unit: %), Tc(550nm) represents the crossed transmittance of the polarizing plate at a wavelength of 550nm (unit: %), and Tc(700nm) represents the crossed transmittance of the polarizing plate at a wavelength of 700nm (unit: %).

[0013] According to another aspect of one or more embodiments of the present invention, an optical display device is provided.

[0014] According to one or more embodiments, an optical display device includes the polarizing plate according to the embodiments.

[0015] According to aspects of one or more embodiments of the present invention, there is provided a polarizing plate that can provide a matte texture and reduce a color difference between a front side and a side side on a screen when an image is displayed on the screen. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a cross-sectional view of a polarizing plate according to an embodiment of the present invention.

[0017] Figure 2 : is a graph showing the relationship between the cross transmittance (Tc) (Y axis, unit: %) and the wavelength (X axis, unit: nm) of the polarizing plates in Example 1 (solid line) and Comparative Example 1 (dashed line).

[0018] Figure 3 is a cross-sectional view of a polarizing plate according to another embodiment of the present invention.

[0019] Figure 4 is a cross-sectional view of a polarizing plate according to another embodiment of the present invention.

[0020] [Explanation of Symbols]

[0021] 10: Polarizer

[0022] 20: First protective film / first protective layer

[0023] 21: Grassroots

[0024] 22: Anti-glare layer

[0025] 23: Anti-reflective layer

[0026] 30: Second protective film / second protective layer DETAILED DESCRIPTION

[0027] Hereinafter, some embodiments of the present invention will be described in more detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention. It should be understood that the present invention can be implemented in different ways and is not limited to the following embodiments.

[0028] The terms used herein are for the purpose of describing some exemplary embodiments and are not intended to limit the present invention. The singular forms "a and an" and "the" used herein are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0029] In the accompanying drawings, parts not related to the description may be omitted for clarity, and the same components will be represented by the same reference numerals throughout the specification. Although the length, thickness or width of various components may be exaggerated in the accompanying drawings for illustrating the present invention, the present invention is not limited thereto.

[0030] In this document, spatially relative terms such as "on" and "below" are defined with reference to the accompanying drawings. Thus, it should be understood that, for example, "upper surface" may be used interchangeably with "lower surface". In addition, when an element (such as a layer or film) is said to be placed "on" another element, the element may be placed directly on the other element, or one or more intervening elements may be present. On the other hand, when an element is said to be placed "directly" "on" another element, there are no intervening elements between the element and the other element.

[0031] In this article, "in-plane retardation (Re)" is a value calculated according to the following equation A:

[0032] Re=(nx-ny)×d,---(A)

[0033] Where nx and ny are the refractive indices of the corresponding optical element when measured in its slow axis direction and fast axis direction at the measurement wavelength, respectively, and d is its thickness (unit: nm). In this article, the in-plane retardation is a value measured by transmitting light in the normal direction of the optical element relative to the in-plane direction.

[0034] Herein, the "internal haze" of the first protective film is a value measured in the same manner as the total haze of the first protective film after spraying alcohol (e.g., ethanol) onto an alkali-free glass plate having a total haze of less than 1%, and then bonding the antiglare layer of the first protective film to the alkali-free glass plate to flatten the unevenness of the surface of the antiglare layer. The "total haze" of the first protective film is a value measured by a typical haze meter relative to the first protective film. The "external haze" of the first protective film may be the difference between the total haze of the first protective film and the internal haze of the first protective film.

[0035] Herein, "haze" may be measured in the visible spectrum, for example at a wavelength of 380 nm to 780 nm.

[0036] Herein, the “single transmittance (Ts)” of a polarizing plate is a value calculated according to (single transmittance in the machine direction (MD) of the polarizing plate+single transmittance in the transverse direction (TD) of the polarizing plate) / 2.

[0037] Herein, the "cross transmittance (Tc)" of the polarizing plate is calculated according to (MD cross transmittance of the polarizing plate×TD cross transmittance of the polarizing plate) / 100.

[0038] "X to Y" used herein to express a specific numerical range refers to values ​​greater than or equal to X and less than or equal to Y.

[0039] The polarizing plate according to an embodiment of the present invention can provide a matte texture of a picture or photo on the screen of an optical display device. The polarizing plate can ensure the clarity of the picture or photo while reproducing the original texture ("matte texture") of the picture or photo, so that the picture or photo looks like a part of the screen, rather than floating above the screen of the optical display device.

[0040] In one or more embodiments, when the optical display device is driven to display an image on the screen, the polarizer can reduce the color value difference between the front and sides of the screen on the screen, thereby preventing or substantially preventing unevenness in screen quality between the front and sides, thereby providing good screen quality.

[0041] In one or more embodiments, a polarizing plate may be used as a polarizing plate that prevents or substantially prevents reflection in a light emitting device display.

[0042] In this regard, a polarizing plate according to one or more embodiments of the present invention includes: a polarizer; and a first protective film stacked on a surface of the polarizer, wherein the first protective film has a total haze of 40% to 60% and an internal haze of 3% to 7%, and the polarizing plate has a transmittance ratio of 4 or less calculated according to the following equation 1 and a transmittance ratio of 20 or more calculated according to the following equation 2:

[0043] Transmittance ratio = Tc(430nm) / Tc(550nm), ---(1)

[0044] Transmittance ratio = Tc(700nm) / Tc(550nm), ---(2)

[0045] Wherein Tc(430nm) represents the orthogonal transmittance of the polarizing plate at a wavelength of 430nm (unit: %), Tc(550nm) represents the orthogonal transmittance of the polarizing plate at a wavelength of 550nm (unit: %), and Tc(700nm) represents the orthogonal transmittance of the polarizing plate at a wavelength of 700nm (unit: %).

[0046] In one or more embodiments, the first protective film has a total haze of 40% to 60% and an internal haze of 3% to 7%. Within this range, the polarizing plate can provide a matte texture of a picture or photo on the screen of the optical display device. In addition, within the range, the polarizing plate can help reduce the color value difference between the front and the side.

[0047] In an embodiment, the first protective film may have a total haze of 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59% or 60%, such as 40% to 55%, or such as 40% to 50%, or such as 43% to 48%. Within the range, the first protective film can ensure a matte texture and can be easily manufactured.

[0048] In an embodiment, the first protective film may have an internal haze of, for example, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5% or 7%, for example, 3% to 6.5%, or for example, 3% to 6%, or for example, 3% to 5%. Within the range, the first protective film can ensure a matte texture and can be easily manufactured.

[0049] In an embodiment, the first protective film may have an external haze of 35% to less than 60%, such as 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58% or 59%, such as 35% to 55%, or such as 40% to 50%, or such as 40% to 45%. Within the range, the above-mentioned total haze and internal haze of the first protective film can be easily achieved.

[0050] In an embodiment, the ratio of the external haze to the internal haze of the first protective film (external haze / internal haze) may be 9 to 20, for example, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19, 19.5 or 20, for example, 10 to 15, or for example, 10 to 13. Within the range, the above-mentioned total haze and internal haze of the first protective film can be easily achieved.

[0051] A first protective film may be stacked on a light incident surface of the polarizer.

[0052] The first protection film may include a base layer and an anti-glare layer stacked on a surface of the base layer.

[0053] The base layer can support the anti-glare layer.

[0054] In an embodiment, each of the internal haze, external haze and total haze of the base layer may be 1% or less, such as 0% to 0.5%. Within the range, the base layer does not affect the total haze and internal haze of the first protective film.

[0055] The base layer may include an optically transparent base film, for example, a base film having a light transmittance of 90% or more in the visible spectrum. The base layer may further include a coating layer formed on at least one surface of the base film.

[0056] In an embodiment, the base layer may be composed only of a base film. The base film may be a film containing an optically transparent resin. For example, the base film may be a film formed of at least one resin selected from the following: a cellulose resin including triacetylcellulose (TAC) and similar materials, a polyester resin including polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate and similar materials, an acrylic resin, a cyclic olefin polymer (COP) resin, a cyclic olefin copolymer (COC) resin, a polycarbonate resin, a polyether sulfone resin, a polysulfone resin, a polyamide resin, a polyimide resin, a polyolefin resin, a polyarylate resin, a polyvinyl alcohol resin, a polyvinyl chloride resin and a polyvinylidene chloride resin. In an embodiment, the base film is a polyethylene terephthalate film or an acrylic film.

[0057] In an embodiment, the base film (eg, base layer) may have an in-plane retardation of 5,000 nm or more, and in an embodiment, 5,000 nm to 15,000 nm, and in an embodiment, 5,000 nm to 12,000 nm at a wavelength of 550 nm. Within the range, the base film may suppress rainbow mura and similar defects.

[0058] In another embodiment, the base film, and in embodiments the base layer, may have an in-plane retardation of less than 5,000 nm, such as 0 to 1,000 nm, such as 0 to 50 nm, at a wavelength of 550 nm.

[0059] The base film may be uniaxially stretched or biaxially stretched to provide the above-mentioned in-plane delay. In an embodiment, the base film may be prepared by preparing an unstretched film from a base film composition comprising a resin, and uniaxially stretching the unstretched film in the longitudinal direction (MD), uniaxially stretching the unstretched film in the transverse direction (TD), or biaxially stretching the unstretched film in MD and TD. The stretch ratio may be appropriately selected in consideration of the thickness of the unstretched film, the target in-plane delay, the stretching temperature, and similar parameters. For example, the stretch ratio may be set to 2 to 7 times, or 3 to 8 times, the initial length of the unstretched film. The stretching temperature may be adjusted according to the glass transition temperature (glass transition temperature) (Tg) of the unstretched film. For example, the stretching temperature may be Tg ± 20°C. Stretching may be performed by typical methods known to those skilled in the art.

[0060] In an embodiment, the base film may be composed only of a base layer having the above-mentioned in-plane retardation at a wavelength of 550 nm.

[0061] In another embodiment, in addition to the base layer having the aforementioned in-plane retardation at a wavelength of 550 nm, the base layer may further include a primer layer as a coating. The primer layer may improve adhesion to an adherend or an anti-glare layer. The primer layer may be formed of a composition including a resin for a primer layer (e.g., a urethane resin, an acrylic resin, a polyester resin, and the like) so as not to affect the effect of the first protective film.

[0062] In an embodiment, the base layer may have a thickness of 50 μm to 100 μm, for example, 60 μm to 90 μm. Within the range, the base layer may serve as a support for the first protective film.

[0063] The anti-glare layer provides the total haze and internal haze of the first protective film.

[0064] The anti-glare layer is directly formed on the base layer. Here, "directly formed" means that the base layer and the anti-glare layer are directly stacked without any adhesive layer, bonding layer, adhesive / bonding layer or any other optical layer in between. The anti-glare layer can be formed by directly coating the composition for the anti-glare layer on the base layer.

[0065] For the anti-glare layer, the surface of the anti-glare layer and / or the composition for the anti-glare layer may be adjusted to achieve the total haze and internal haze of the first protective film.

[0066] In an embodiment, fine roughness may be formed on a surface of the anti-glare layer, for example, a surface of the anti-glare layer opposite to the base layer.

[0067] Fine roughness may be formed on the anti-glare layer including inorganic particles and / or organic particles. Due to the fine roughness, the anti-glare layer may have a total haze and an internal haze within a suitable range.

[0068] Now, the organic particles contained in the anti-glare layer will be described. The organic particles may be contained in the composition for the anti-glare layer, and may have a refractive index different from that of the matrix for the anti-glare layer, so that the haze of the first protective film can be adjusted and the effect of the present invention can be improved by providing the anti-glare layer with a surface roughness Sa in a certain range (e.g., a predetermined range).

[0069] In an embodiment, in the anti-glare layer, the organic particles may be 5 wt % to 50 wt %, for example 5 wt %, 6 wt %, 7 wt %, 8 wt %, 9 wt %, 10 wt %, 11 wt %, 12 wt %, 13 wt %, 14 wt %, 15 wt %, 16 wt %, 17 wt %, 18 wt %, 19 wt %, 20 wt %, 21 wt %, 22 wt %, 23 wt %, 24 wt %, 25 wt %, 26 wt %, 27 wt %, %, 28 wt%, 29 wt%, 30 wt%, 31 wt%, 32 wt%, 33 wt%, 34 wt%, 35 wt%, 36 wt%, 37 wt%, 38 wt%, 39 wt%, 40 wt%, 41 wt%, 42 wt%, 43 wt%, 44 wt%, 45 wt%, 46 wt%, 47 wt%, 48 wt%, 49 wt% or 50 wt%, for example 10 wt% to 40 wt%, or for example 10 wt% to 20 wt% is present. Within this range, the organic particles can provide an anti-glare effect.

[0070] The organic particles may be any of microparticles, nanoparticles, and the like, and may have any suitable shape (e.g., spherical, amorphous, and the like), but are not limited thereto. In an embodiment, the organic particles may have an average particle diameter (D50) of 0.01 μm to 6 μm. Within this range, the organic particles may provide an anti-glare effect. The organic particles are contained in a composition including a resin for an anti-glare layer and may have an average particle diameter (D50) of 0.5 μm to 5.5 μm, for example, 1 μm to 5 μm, for forming an anti-glare layer.

[0071] The “average particle size (D50)” used herein refers to a typical average particle size (D50) known to those skilled in the art, and refers to a particle size corresponding to 50% by volume of organic particles when the organic particles are distributed in order from smallest to largest in volume.

[0072] In an embodiment, the organic particles have a higher refractive index than the matrix for the anti-glare layer, and may have a refractive index of 1.30 to 1.70, for example, 1.40 to 1.60. Within this range, the organic particles may easily form the anti-glare layer according to the present invention.

[0073] The organic particles may be appropriately selected from organic particles having the above-mentioned refractive index.

[0074] For example, although the organic particles may include core-shell organic particles, in an embodiment, the organic particles are non-core-shell particles, i.e., organic particles composed of a single material. The single material used for the organic particles may be any polyacrylate particles, poly(methylmethacrylate) (PMMA) particles, polystyrene (PS) particles, silicone particles, polycarbonate particles, polyolefin particles, polyester particles, polyamide particles, polyimide particles, polyvinyl fluoride particles, poly(methylmethacrylate)-polyacrylate particles, polyacrylate-polystyrene particles, melamine particles, and the like. In an embodiment, the organic particles are a mixture of polystyrene particles and polyacrylate particles or polymethacrylate particles.

[0075] The anti-glare layer may include organic particles and a matrix for the anti-glare layer in which the organic particles are dispersed, and the matrix for the anti-glare layer may have a refractive index lower than that of the organic particles. The anti-glare layer may be formed by a composition comprising organic particles and an actinic radiation-curable compound. The actinic radiation-curable compound may include an actinic radiation-curable resin or oligomer and an actinic radiation-curable monomer. The actinic radiation-curable resin or oligomer may be selected from any suitable type known to those skilled in the art.

[0076] The composition may further include at least one photoinitiator selected from a photoradical initiator and a photocationic initiator. The photoinitiator can cure actinic radiation-curable resins and actinic radiation-curable monomers. The photoradical initiator may include a photoradical initiator, such as an acetophenone-based initiator, a cyclohexyl ketone-based initiator, and the like.

[0077] In an embodiment, the composition may include, based on solid content: 5 wt % to 50 wt %, for example 10 wt % to 40 wt %, or for example 10 wt % to 20 wt % of organic particles; 20 wt % to 80 wt %, for example 50 wt % to 70 wt % of actinic radiation-curable resin or oligomer; 10 wt % to 80 wt %, for example 10 wt % to 30 wt % of actinic radiation-curable monomer; and 1 wt % to 10 wt % of photoinitiator.

[0078] The composition for the anti-glare layer may include any suitable solvent in an amount that does not dissolve the organic particles. The solvent may be any one of methyl ethyl ketone, propylene glycol methyl ether, and similar solvents, but is not limited thereto.

[0079] The composition for the anti-glare layer may also include typical additives that may be included in the anti-glare layer. The anti-glare layer may be formed by depositing the composition for the anti-glare layer on the surface of the base layer, followed by drying and curing. Curing may be performed by typical methods known to those skilled in the art, such as any of heat curing, light curing, and the like.

[0080] In an embodiment, the anti-glare layer may have a thickness of 2 μm to 10 μm, for example, 3 μm to 7 μm. Within this range, the anti-glare layer may be included in the first protective film.

[0081] The first protective film may further include an anti-reflection layer stacked on a surface of the anti-glare layer.

[0082] The anti-reflection layer can effectively achieve the effect of the present invention by reducing the reflectivity of the polarizing plate having the first protective film.

[0083] In an embodiment, the anti-reflection layer may be directly formed on the anti-glare layer. Here, "directly formed" means that the anti-reflection layer is disposed on the anti-glare layer without any adhesive layer, bonding layer, adhesive / bonding layer or any other optical layer therebetween. In an embodiment, the anti-reflection layer may be formed by directly coating the composition for the anti-reflection layer on the anti-glare layer.

[0084] In an embodiment, the anti-reflection layer may have a refractive index of 2.0 or less, for example, 1.2 to 1.4. Within this range, the anti-reflection layer can easily provide an anti-reflection effect. The anti-reflection layer can provide the reflectivity of the film by adjusting the composition for the anti-reflection layer.

[0085] The composition for the anti-reflection layer may include at least one selected from inorganic particles and fluorine compounds. The inorganic particles and the fluorine compounds may reduce the refractive index of the anti-reflection layer.

[0086] In an embodiment, the inorganic particles may have a hollow shape to provide a low refractive index. For example, the inorganic particles may be inorganic particles with a low refractive index, and in an embodiment, hollow silica. In an embodiment, the inorganic particles may have a refractive index less than 1.5, for example, 1.0 to less than 1.5. Within this range, the inorganic particles can easily reduce the refractive index of the anti-reflection layer.

[0087] The inorganic particles have an average particle size (D50) smaller than the thickness of the anti-reflection layer, thereby easily achieving the surface roughness Sa of the anti-reflection layer. In an embodiment, the inorganic particles may have an average particle size (D50) of 50 nm to 150 nm, for example, 50 nm to 120 nm.

[0088] In an embodiment, in the anti-reflection layer, the inorganic particles may be present in an amount of 30 wt % to 70 wt %, such as 40 wt % to 60 wt %, or such as 50 wt % to 60 wt %. Within this range, the anti-reflection layer can easily achieve the reflectivity of the present invention.

[0089] The fluorine-based compound can make it easy to reduce the refractive index of the anti-reflection layer even if a small amount of inorganic particles is used. The fluorine-based compound may include a fluorine-containing (meth)acrylate monomer, an oligomer thereof, or a resin thereof.

[0090] In addition to the inorganic particles and the fluorine compound, the composition for the anti-reflection layer may also include at least one selected from an actinic radiation-curable resin or oligomer and an actinic radiation-curable monomer and a photoinitiator. The actinic radiation-curable resin and the actinic radiation-curable monomer may be cured to facilitate the formation of a matrix for the anti-reflection layer and to allow particles with a low refractive index to be stably contained in the anti-reflection layer. The actinic radiation-curable resin, the actinic radiation-curable monomer and the photoinitiator may be the same as those described above in the anti-glare layer.

[0091] In an embodiment, the composition for an anti-reflection layer may include, based on solid content: 20 wt % to 80 wt % of at least one selected from an actinic radiation curable resin, an actinic radiation curable oligomer, and an actinic radiation curable monomer; 30 wt % to 70 wt % and in an embodiment 50 wt % to 70 wt % of inorganic particles; 1 wt % to 10 wt % of a fluorine compound and 1 wt % to 10 wt % of a photoinitiator. Within this range, the composition can easily form an anti-reflection layer according to the present invention.

[0092] The composition for the anti-reflection layer may also include typical additives that may be included in the anti-reflection layer. For example, the additives may impart antifouling function and thinness to the anti-reflection layer, and may include typical additives known to those skilled in the art. The additives may include at least one selected from fluorine-containing additives and silicone-based additives. The anti-reflection layer may be formed by depositing the composition for the anti-reflection layer on the surface of the base layer, followed by drying and curing. Curing may be performed by typical methods known to those skilled in the art, such as any of heat curing, photocuring, and the like.

[0093] In an embodiment, the anti-reflection layer may have a thickness of 60 nm to 200 nm, and in an embodiment, 80 nm to 150 nm. Within this range, the anti-reflection layer may be included in the first protective film.

[0094] The first protective film may be stacked on the polarizer in a typical manner. For example, the first protective film may be stacked on the polarizer via a bonding layer formed by a water-based bonding agent or a photocurable bonding agent.

[0095] By using the first protective film having the above-mentioned total haze and internal haze, the polarizing plate can provide a matte texture of a picture or photo on the screen of the optical display device. By further satisfying the transmittance ratio of equations 1 and 2, when the optical display device is operated to display an image on the screen, the polarizing plate can reduce the color value difference between the front and the side, thereby ensuring excellent screen quality without uneven screen quality between the front and the side.

[0096] In an embodiment, the polarizing plate has a transmittance ratio of 4 or less calculated according to the following Equation 1 and a transmittance ratio of 20 or more calculated according to the following Equation 2:

[0097] Transmittance ratio = Tc(430nm) / Tc(550nm), ---(1)

[0098] Transmittance ratio = Tc(700nm) / Tc(550nm), ---(2)

[0099] Wherein Tc(430nm) represents the orthogonal transmittance of the polarizing plate at a wavelength of 430nm (unit: %), Tc(550nm) represents the orthogonal transmittance of the polarizing plate at a wavelength of 550nm (unit: %), and Tc(700nm) represents the orthogonal transmittance of the polarizing plate at a wavelength of 700nm (unit: %).

[0100] Within the above range, the polarizing plate including the first protective film having the above total haze and internal haze can easily reduce the color value difference between the front and side surfaces on the screen.

[0101] In an embodiment, the polarizing plate has a transmittance ratio of 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9 or 4.0, such as 1.5 to 4.0, or such as 2.0 to 4.0, calculated according to Equation 1. Within this range, a polarizing plate having the aforementioned effects without affecting the matte texture can be easily manufactured.

[0102] In embodiments, the polarizing plate may have a transmittance ratio of 20.0, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39 or 40, for example, 20.0 to 30.0, calculated according to Equation 2. Within this range, a polarizing plate having the aforementioned effects without affecting the matte texture may be easily manufactured.

[0103] The orthogonal transmittance of the polarizing plate at wavelengths of 430nm, 550nm and 700nm is selected to ensure excellent screen quality by reducing the color value difference between the front and the side in the polarizing plate including the protective film having the above haze value, without uneven screen quality between the front and the side.

[0104] In an embodiment, the polarizing plate may have an orthogonal transmittance of 0.009% or less, such as 0.001%, 0.002%, 0.003%, 0.004%, 0.005%, 0.006%, 0.007%, 0.008% or 0.009%, such as 0.001% to 0.009%, or such as 0.002% to 0.0085% at a wavelength of 430nm. Within this range, the polarizing plate can easily achieve the transmittance ratio of equation 1.

[0105] In an embodiment, the polarizing plate may have an orthogonal transmittance of 0.005% or less, such as 0.0001%, 0.0005%, 0.001%, 0.002%, 0.003%, 0.004% or 0.005%, or such as 0.0001% to 0.005%, or such as 0.001% to 0.005%, at a wavelength of 550nm. Within this range, the polarizing plate can easily achieve the transmittance ratio of equations 1 and 2.

[0106] In an embodiment, the polarizing plate may have an orthogonal transmittance of 0.035% or more, such as 0.035%, 0.040%, 0.045%, 0.050%, 0.055%, 0.060%, 0.065%, 0.070%, 0.075%, 0.080%, 0.085% or 0.090%, or such as 0.035% to 0.090%, or such as 0.040% to 0.070% at a wavelength of 700nm. Within this range, the polarizing plate can easily achieve the transmittance ratio of equation 2.

[0107] For the polarizing plate, the ratio of 4 or less calculated according to equation 1 and the ratio of 20 or more calculated according to equation 2 can be achieved by the polyvinyl alcohol film and the polarizer manufactured by the following manufacturing process, but is not particularly limited thereto. In an embodiment, the polarizing plate includes the above-mentioned polarizer and the first protective film, thereby achieving the ratio of 4 or less according to equation 1 and the ratio of 20 or more according to equation 2.

[0108] The polarizer includes a light absorbing polarizer that splits incident light into two orthogonal polarized components and transmits one polarized component while absorbing the other polarized component.

[0109] The polarizer may include a uniaxially stretched polarizer containing a dichroic dye. In an embodiment, the polarizer containing a dichroic dye may include a polarizer manufactured by uniaxially stretching a base film for a polarizer on an MD and dyeing the stretched base film with a dichroic dye (e.g., iodine or an iodine-containing substance including potassium iodide). The base film for the polarizer may include a polyvinyl alcohol-based film or a derivative thereof, but is not limited thereto.

[0110] In an embodiment, the polarizer may have a thickness of 1 μm to 40 μm, for example, 15 μm to 30 μm, or for example, 17 μm to 20 μm. Within this range, the polarizer may be used in a polarizing plate.

[0111] The polyvinyl alcohol film may contain a hydrophilic functional group and a hydrophobic functional group. In addition to the hydroxyl group (OH) present as a hydrophilic functional group in the polyvinyl alcohol film, there is also a hydrophobic functional group. The polyvinyl alcohol film containing both the hydrophilic functional group and the hydrophobic functional group is prepared by the following process, and the polarizing plate according to the present invention can easily achieve the effect of the present invention.

[0112] The hydrophobic functional group exists in the main chain and / or side chain of the polyvinyl alcohol resin constituting the polyvinyl alcohol film. "Main chain" refers to the part of the main skeleton constituting the polyvinyl alcohol resin, and "side chain" refers to the skeleton connected to the main chain. In an embodiment, the hydrophobic functional group exists in the main chain of the polyvinyl alcohol resin.

[0113] In an embodiment, the polyvinyl alcohol resin containing a hydrophilic functional group and a hydrophobic functional group can be prepared by polymerizing at least one vinyl ester monomer (e.g., vinyl acetate, vinyl formate, vinyl propionate, vinyl butyrate, vinyl pivalate, and isopropenyl acetate) with a monomer providing a hydrophobic functional group. In an embodiment, the vinyl ester monomer includes vinyl acetate. The monomer providing a hydrophobic functional group may include a monomer providing a hydrocarbon repeating unit including ethylene, propylene, or the like.

[0114] In an embodiment, the polyvinyl alcohol film may have a thickness of 50 μm or less, for example, 10 μm to 50 μm. Within this range, the polyvinyl alcohol film does not melt and break when stretched.

[0115] As described below, a polarizer may be manufactured by subjecting a polyvinyl alcohol film to dyeing, stretching, cross-linking, color correction, and drying processes. The order of the dyeing, stretching, and cross-linking processes may vary depending on the type of the polyvinyl alcohol film and the polarizer manufacturing process.

[0116] The dyeing process includes treating the polyvinyl alcohol film in a dyeing bath containing a dichroic substance. In the dyeing process, the polyvinyl alcohol film is immersed in the dyeing bath containing the dichroic substance. The dyeing bath containing the dichroic substance includes an aqueous solution containing the dichroic substance and boric acid. Since the dyeing bath contains both the dichroic substance and the boron compound, the polyvinyl alcohol film can be prevented or substantially prevented from being broken even when dyeing and stretching are performed under the following stretching conditions.

[0117] The dichroic substance is an iodine-containing substance and may include at least one selected from iodine (I2), potassium iodide, hydrogen iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, and copper iodide. In an embodiment, the dichroic substance may be present in the dye bath (e.g., in the dye aqueous solution) in an amount of 0.5 mol / ml to 10 mol / ml, and in an embodiment, 0.5 mol / ml to 5 mol / ml. Within this range, uniform deposition may be obtained.

[0118] The boron compound can help prevent the polyvinyl alcohol film from melting and breaking when the polyvinyl alcohol film is stretched. The boron compound can help prevent the polyvinyl alcohol film from melting and breaking in the stretching process after the dyeing process, even when the polyvinyl alcohol film is stretched at a high temperature and a high stretch ratio.

[0119] The boron compound may include at least one selected from boric acid and borax. In an embodiment, the boron compound may be present in the dye bath in an amount of 0.1 wt % to 5 wt %, and in an embodiment, 0.3 wt % to 3 wt %, and in an embodiment, in the dye aqueous solution. Within this range, the polyvinyl alcohol film does not melt and crack during the stretching process, and high reliability can be achieved.

[0120] In an embodiment, the dyeing solution may have a temperature of 20° C. to 50° C., and in an embodiment, 25° C. to 40° C. In an embodiment, in the dyeing process, the polyvinyl alcohol film may be immersed in the dyeing bath for 30 seconds to 120 seconds, and in an embodiment, for 40 seconds to 80 seconds. Within these ranges, the polarizer of the polarizing plate according to the present invention can be easily manufactured.

[0121] The stretching process includes stretching the dyed polyvinyl alcohol film at a temperature of 57° C. or more, for example, 57° C. to 65° C., and at a stretching ratio of 5.7 times or more, for example, 5.7 times to 7 times.

[0122] The stretching process may be performed by wet stretching or dry stretching. In an embodiment, the stretching process includes wet stretching so that the boron compound is applied during the stretching process. The wet stretching includes uniaxially stretching the polyvinyl alcohol film in a machine direction (MD) in an aqueous solution containing the boron compound.

[0123] The boron compound may include at least one selected from boric acid and borax. In an embodiment, the boron compound may be present in the stretching bath in an amount of 0.1 wt % to 5 wt %, and in an embodiment, 0.3 wt % to 5 wt %, and in an embodiment, in the stretching aqueous solution. Within this range, the polyvinyl alcohol film does not melt and crack during the stretching process, and high reliability can be achieved.

[0124] In an embodiment, the stretching solution has a temperature of 57°C or greater, such as 57°C to 65°C.

[0125] The cross-linking process is performed to enhance the adsorption of the dichroic material to the stretched polyvinyl alcohol film. The cross-linking solution used in the cross-linking process may include a boron compound. The boron compound may contribute to the strong adsorption of the dichroic material even when the polarizer is under thermal shock conditions, while improving the reliability of the polarizer.

[0126] The boron compound may include at least one selected from boric acid and borax. In an embodiment, the boron compound may be present in the crosslinking bath in an amount of 0.5 wt % to 10 wt %, and in an embodiment, 1 wt % to 5 wt %, and in an embodiment, in the crosslinking aqueous solution. Within this range, the polyvinyl alcohol film does not melt and crack during the stretching process, and high reliability can be achieved.

[0127] The cross-linking bath may have a temperature of 20 to 50° C., and in embodiments 25 to 40° C. The cross-linking process may be performed by immersing the polyvinyl alcohol film in the cross-linking bath for 30 to 120 seconds, and in embodiments 40 to 80 seconds.

[0128] In the cross-linking process, the polyvinyl alcohol film is further uniaxially stretched in the MD. The additional stretching can promote the polarizing plate to reach the ratio of equation 1 and equation 2.

[0129] The color correction process can improve the durability of the polarizer. The color correction bath may include a color correction solution containing greater than 0 wt % to 10 wt %, and in embodiments, 1 wt % to 5 wt % potassium iodide. The color correction solution may have a temperature of 20° C. to 50° C., and in embodiments, 25° C. to 40° C. The color correction process may be performed by immersing the polyvinyl alcohol film in the color correction bath for 5 seconds to 50 seconds, and in embodiments, 5 seconds to 20 seconds.

[0130] In the color correction process, the polyvinyl alcohol film is further uniaxially stretched in the MD. The additional stretching can promote the polarizing plate to reach the ratio of equation 1 and equation 2.

[0131] The drying process may be performed by drying the polyvinyl alcohol film at 60 to 90° C., and in embodiments at 70 to 90° C., for 30 seconds to 10 minutes, and in embodiments for 30 seconds to 5 minutes. The drying process may be performed by hot air drying, but is not limited thereto.

[0132] The transmittance ratio of the above equations 1 and 2 can be achieved by adjusting the MD uniaxial stretch ratio not only in the wet stretching bath but also in the cross-linking bath and the color correction bath in the polarizer manufacturing process. Each MD uniaxial stretch ratio or all MD uniaxial stretch ratios in the cross-linking bath and the color correction bath can be adjusted to be lower than the MD uniaxial stretch ratio in the wet stretching bath and at most three times the MD uniaxial stretch ratio in the wet stretching bath.

[0133] Prior to the dyeing process, the polyvinyl alcohol film may be subjected to a washing process and / or a swelling process.

[0134] In the washing process, the polyvinyl alcohol film is washed with water to remove foreign substances from the polyvinyl alcohol film.

[0135] In the swelling process, the polyvinyl alcohol film is immersed in a swelling bath of a certain temperature range (e.g., a predetermined temperature range) to facilitate dyeing with a dichroic material and stretching. In an embodiment, the swelling process may be performed at 15° C. to 35° C., and in an embodiment at 20° C. to 30° C. for 30 seconds to 50 seconds.

[0136] In an embodiment, the polarizer may have a polarization degree of 95% or more, and in an embodiment, 95% to 100%, and in an embodiment, 98% to 100%. Within this range, the polarizing plate can easily achieve the effects of the present invention.

[0137] The polarizing plate may further include a second protective layer stacked on the other surface of the polarizer (a light exit surface of the polarizer).

[0138] The second protective layer may be a retardation film that can provide an anti-reflection effect. For example, the second protective layer may have an in-plane retardation of 100 nm to 150 nm at a wavelength of 550 nm.

[0139] The second protective layer may include a liquid crystal layer and / or a non-liquid crystal layer.The second protective layer may be a single-layer coating or film or a multi-layer coating or film.

[0140] In an embodiment, the second protective layer may be composed of a single liquid crystal layer or a plurality of liquid crystal layers. The liquid crystal layer may be formed of a typical composition for a liquid crystal layer known to those skilled in the art.

[0141] In another embodiment, the second protection layer may be a non-liquid crystal retardation film.

[0142] For example, the second protective layer may be a stretched film formed of at least one resin selected from the following: cellulose resins including triacetyl cellulose (TAC) and similar materials, polyester resins including polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate (PEN), polybutylene naphthalate and similar materials, cyclic polyolefin resins, polycarbonate resins, polyether sulfone resins, polysulfone resins, polyamide resins, polyimide resins, polyolefin resins, polyarylate resins, polyvinyl alcohol resins, polyvinyl chloride resins and polyvinylidene chloride resins.

[0143] In another example, the second protective layer includes a first retardation layer and a second retardation layer stacked on the surface of the first retardation layer, wherein the first retardation layer is a non-liquid crystal retardation film, and the second retardation layer is a non-liquid crystal coating. The second retardation layer can be directly formed on the first retardation layer, or can be stacked on the first retardation layer through an adhesive layer or a bonding layer.

[0144] In an embodiment, the first retardation layer exhibits positive dispersion and may have an in-plane retardation of 180 nm to 250 nm at a wavelength of 550 nm. Within this range, the first retardation layer may be combined with the second retardation layer to provide an anti-reflection effect.

[0145] The non-liquid crystal retardation film may be a film formed of at least one resin selected from the following: cellulose resin including triacetyl cellulose (TAC) and similar materials, polyester resin including polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate (PEN), polybutylene naphthalate and similar materials, cycloolefin polymer (COP) resin, cycloolefin copolymer (COC) resin, polycarbonate resin, polyethersulfone resin, polysulfone resin, polyamide resin, polyimide resin, polyolefin resin, polyarylate resin, polyvinyl alcohol resin, polyvinyl chloride resin and polyvinylidene chloride resin. In an embodiment, the non-liquid crystal retardation film is a cycloolefin polymer (COP) film or a cycloolefin copolymer (COC) film.

[0146] In an embodiment, the second retardation layer exhibits positive dispersion and may have an in-plane retardation of 100 nm to 160 nm at a wavelength of 550 nm. Within this range, the second retardation layer may be combined with the first retardation layer to provide an anti-reflection effect.

[0147] The non-liquid crystal coating layer may be formed of a composition for a retardation layer including a resin having negative intrinsic birefringence.

[0148] The resin having negative intrinsic birefringence includes a polymer having negative intrinsic birefringence. The polymer having negative intrinsic birefringence may include, for example, at least one selected from homopolymers of styrene or styrene derivatives, polystyrene polymers including copolymers of styrene or styrene derivatives and comonomers, polyacrylonitrile polymers, poly(methyl methacrylate) copolymers, and cellulose copolymers including cellulose esters, but is not limited thereto. The comonomer may include at least one selected from acrylonitrile, maleic anhydride, methyl methacrylate, and butadiene. In an embodiment, the second retardation layer may include at least one selected from polystyrene and cellulose compounds.

[0149] In an embodiment, the cellulose compound may include a cellulose ester polymer including at least one unit in which at least some hydrogen atoms of a hydroxyl group [C2 hydroxyl group, C3 hydroxyl group, or C6 hydroxyl group] of a sugar monomer constituting cellulose are substituted with an acyl group, as shown by the following Formula 1. Here, the acyl group may be substituted or unsubstituted.

[0150] Formula 1

[0151]

[0152] Wherein n is an integer of 1 or greater.

[0153] In an embodiment, the polystyrene system may include a repeating unit of Formula 2 below:

[0154]

[0155] in is the attachment site; R 1 , R 2 and R 3 Each R is independently a hydrogen atom, an alkyl group, a substituted alkyl group, or a halogen; each R is independently an alkyl group, a substituted alkyl group, a halogen, a hydroxyl group, a carboxyl group, a nitro group, an alkoxy group, an amino group, a sulfonate group, a phosphate group, an acyl group, an acyloxy group, a phenyl group, an alkoxycarbonyl group, or a cyano group, 1 , R 2 and R 3 At least one of is halogen and / or at least one R is halogen; and n is an integer from 0 to 5.

[0156] In embodiments, halogen refers to fluorine (F), Cl, Br or I, and in embodiments, is F.

[0157] Figure 1 is a cross-sectional view of a polarizing plate according to an embodiment of the present invention. Figure 1 , the polarizing plate may include a polarizer 10, a first protective film or a first protective layer 20 stacked on an upper surface of the polarizer 10, and a second protective film or a second protective layer 30 stacked on a lower surface of the polarizer 10. Figure 1 Although not shown, an adhesive layer or a bonding layer may be inserted between the polarizer 10 and the first protective film 20 , between the polarizer 10 and the second protective film 30 , and / or on the lower surface of the second protective film 30 .

[0158] Figure 3 is a cross-sectional view of a polarizing plate according to another embodiment of the present invention. Figure 3 , the polarizing plate may include a polarizer 10, a base layer 21 and an anti-glare layer 22 sequentially stacked on an upper surface of the polarizer 10, and a second protective film or a second protective layer 30 stacked on a lower surface of the polarizer 10. Figure 3 Although not shown, an adhesive layer or a bonding layer may be inserted between the polarizer 10 and the base layer 21 , between the polarizer 10 and the second protective film 30 , and / or on the lower surface of the second protective film 30 .

[0159] Figure 4 is a cross-sectional view of a polarizing plate according to another embodiment of the present invention. Figure 4 The polarizing plate may include a polarizer 10, a base layer 21, an anti-glare layer 22, and an anti-reflection layer 23 sequentially stacked on an upper surface of the polarizer 10, and a second protective film or a second protective layer 30 stacked on a lower surface of the polarizer 10. Figure 4 Although not shown, an adhesive layer or a bonding layer may be inserted between the polarizer 10 and the base layer 21 , between the polarizer 10 and the second protective film 30 , and / or on the lower surface of the second protective film 30 .

[0160] In embodiments, the polarizing plate may have a ratio of 0.25 or less, for example, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, or 0.25, for example, 0.08 to 0.25, for example, 0.1 to 0.2, or for example, 0.1 to 0.15, calculated according to the following equation 3,

[0161] Ratio = Tc(700nm) / (haze×0.01), ---(3)

[0162] Herein, haze represents the total haze of the first protective film (unit: %), and Tc (700 nm) represents the orthogonal transmittance of the polarizing plate at a wavelength of 700 nm (unit: %).

[0163] Within this range, the polarizing plate can achieve further improvement in the effectiveness of the present invention.

[0164] Equation 3 may be a criterion for judging whether the polarizing plate provides a matte texture of a picture or photo on the screen of the optical display device and reduces the color value difference between the front and side of the optical display device on the screen. Equation 3 may be implemented by adjusting the orthogonal transmittance of the polarizing plate and the total haze of the first protective film at a wavelength of 770 nm.

[0165] In an embodiment, the optical display device includes a polarizing plate according to an embodiment of the present invention. In an embodiment, the optical display device may include a light emitting device display, wherein the light emitting device display includes any one of an inorganic light emitting device, an organic light emitting device, an organic / inorganic light emitting device, and the like.

[0166] Next, the present invention will be further described in detail with reference to some examples. However, it should be understood that these examples are provided for illustration and should not be interpreted as limiting the present invention in any way.

[0167] Example 1

[0168] (1) Manufacturing of polarizer

[0169] A polyvinyl alcohol film (VF-TS#4500, thickness: 45 μm, Kuraray Co., Ltd.) washed with water at 25° C. was subjected to swelling treatment with water in a swelling bath at 30° C.

[0170] After the swelling treatment, the polyvinyl alcohol film was immersed in a dyeing bath containing an aqueous solution containing 1 mol / ml potassium iodide and 1 wt% boric acid for 65 seconds at 30° C. After the dyeing treatment, the film was uniaxially stretched to 5.7 times in the MD of the film in a wet stretching bath containing a 3 wt% boric acid aqueous solution at 60° C. The stretched film was treated in a cross-linking bath containing a 3 wt% boric acid aqueous solution at 25° C. for 65 seconds while being uniaxially stretched in the MD.

[0171] After the cross-linking treatment, the film was immersed in a color correction bath containing a 4.5 wt % potassium iodide aqueous solution at 30° C. for 10 seconds while being uniaxially stretched in MD. After the color correction, the film was washed with water and dried with hot air at 80° C. for 1 minute, thereby preparing a polarizer (thickness: 17 μm).

[0172] (2) Manufacturing of polarizing plates

[0173] A photocurable adhesive was applied to both surfaces of the prepared polarizer. A polarizing plate was manufactured by bonding a first protective film (LRB2-80PET) to the upper surface of the polarizer and bonding two second protective films (a laminate of QLAA228 (half wave plate, HWP) and QLAB228 (quarter wave plate, QWP)) to the lower surface thereof. The first protective film had an internal haze of 4%, an external haze of 41%, and a total haze of 45%.

[0174] Example 2

[0175] A polarizer was prepared in the same manner as in Example 1, except that the MD uniaxial stretching ratio was changed in the wet stretching, crosslinking, and color correction baths. A polarizing plate was prepared in the same manner as in Example 1, except that the prepared polarizer was used and a retardation layer (ZA-QWP, a non-liquid crystal cellulose ester coating layer formed on a COP film) was used as a second protective film.

[0176] Example 3

[0177] A polarizer was prepared in the same manner as in Example 1, except that the MD uniaxial stretching ratio was changed in the wet stretching, crosslinking, and color correction baths. A polarizing plate was prepared in the same manner as in Example 1, except that the prepared polarizer was used and a retardation layer (ZA-QWP) was used as a second protective film.

[0178] Comparative Examples 1 to 4

[0179] A polarizer was prepared in the same manner as in Example 2, and a polarizing plate was prepared in the same manner as in Example 2 using the prepared polarizer, except that the MD uniaxial stretching ratio was changed in the wet stretching, crosslinking, and color correction baths.

[0180] The properties of the polarizing plates of the examples and comparative examples were evaluated and listed in Table 1. The results are shown in Table 1 and Figure 2 Shown in.

[0181] (1) Orthogonal transmittance of polarizing plate (Tc, unit: %): The polarizing plate of each of the examples and comparative examples was placed in a transmittance meter V-7100 (JASCO Co., Ltd.), and the orthogonal transmittance at wavelengths of 430 nm, 550 nm, and 700 nm was measured by transmitting light from the first protective film side to the polarizer in the normal direction relative to the in-plane direction of the polarizing plate. The transmittance ratios of Equations 1, 2, and 3 were calculated based on the measured orthogonal light transmittance.

[0182] (2) Color values ​​x, y and color value difference between the front and side: The polarizing plates manufactured in each of the examples and comparative examples were stacked on an organic light-emitting device panel to make a model. Using EZ-Contrast XL-88, color coordinates x and y were obtained at the front (0°, 0°) and the side (60°, 0°). The distance between the front (0°, 0°) and the side (60°, 0°) was calculated as △(x, y). △(x, y) less than or equal to 0.005 indicates that the color value difference between the front and the side is small, and means that the unevenness of the color value between the front and the side is difficult to detect with the naked eye, thereby providing good screen quality between the front and the side.

[0183] (3) Matt texture: Assemble the same model as in (2). Evaluate with the naked eye whether the picture or photograph is clearly visible, and when the model is operated to display the picture or photograph, whether the picture or photograph is reproduced with the original texture of the picture or photograph (mat texture) so that the picture or photograph looks like a part of the screen rather than floating above the screen. Reproduction of the original texture of the painting or photograph is rated as good, and failure to reproduce the original texture of the painting or photograph by displaying an unclear painting or photograph is rated as poor.

[0184] Table 1

[0185]

[0186] As shown in Table 1, when the optical display device is not operating, the polarizing plate including the first protective film according to the embodiment of the present invention realizes a matte texture of a picture or photo on the screen of the optical display device. In addition, the polarizing plate according to the embodiment of the present invention satisfies the ratio of equations 1 and 2, thereby reducing the color value difference between the front and side of the screen when the optical display device is operating.

[0187] In contrast, as shown in Table 1, the polarizing plate of the comparative example not satisfying the ratios of Equation 1 and Equation 2 exhibits a significant color value difference between the front and side surfaces, and allows for easy recognition of unevenness in color value between the front and side surfaces.

[0188] In addition, if Figure 2 As shown, it can be seen that the polarizing plate of Example 1 has a lower orthogonal transmittance at a wavelength of 430nm and a higher orthogonal transmittance at a wavelength of 700nm compared to the polarizing plate of Comparative Example 1, thereby providing different orthogonal transmittances at wavelengths of 430nm and 700nm. The results mean that even if the same first protective film is used, the orthogonal transmittance of the polarizing plate needs to be adjusted to provide the effect of the present invention.

[0189] Although some exemplary embodiments have been described herein, it should be understood that various modifications, changes, variations, and equivalent embodiments may be made by those skilled in the art without departing from the spirit and scope of the invention.

Claims

1. A polarizing plate, comprising: polarizer; as well as a first protective film, stacked on the surface of the polarizer, The first protective film has a total haze of 40% to 60% and an internal haze of 3% to 7%, and The polarizing plate has a transmittance ratio of 4 or less calculated according to the following equation 1 and a transmittance ratio of 20 or more calculated according to the following equation 2: Transmittance ratio = Tc(430nm) / Tc(550nm), ---(1) Transmittance ratio = Tc(700nm) / Tc(550nm), ---(2) in Tc(430nm) represents the orthogonal transmittance of the polarizing plate at a wavelength of 430nm, wherein the unit of Tc(430nm) is %. Tc(550nm) represents the orthogonal transmittance of the polarizing plate at a wavelength of 550nm, wherein the unit of Tc(550nm) is %, and Tc(700nm) represents the orthogonal transmittance of the polarizing plate at a wavelength of 700nm, wherein the unit of Tc(700nm) is %. 2 . The polarizing plate according to claim 1 , wherein the orthogonal transmittance of the polarizing plate at a wavelength of 430 nm is 0.009% or less. 3 . The polarizing plate according to claim 1 , wherein the orthogonal transmittance of the polarizing plate at a wavelength of 550 nm is 0.005% or less. 4 . The polarizing plate according to claim 1 , wherein the cross transmittance of the polarizing plate at a wavelength of 700 nm is at least 0.035%. 5 . The polarizing plate according to claim 1 , wherein a ratio of external haze to internal haze of the first protective film is in a range of 9 to 20. 6 . The polarizing plate according to claim 1 , wherein the first protective film comprises a base layer and an anti-glare layer stacked on a surface of the base layer. 7 . The polarizing plate according to claim 6 , further comprising an anti-reflection layer stacked on a surface of the anti-glare layer.

8. The polarizing plate according to claim 1, wherein the polarizing plate has a ratio calculated according to the following Equation 3 of 0.25 or less, Ratio = Tc(700nm) / (haze×0.01), ---(3) Wherein the haze represents the total haze of the first protective film, wherein the unit of the haze is %, and Tc(700nm) represents the orthogonal transmittance of the polarizing plate at a wavelength of 700nm, wherein the unit of Tc(700nm) is %. 9 . The polarizing plate according to claim 1 , further comprising a second protective film stacked on the other surface of the polarizer. 10 . The polarizing plate according to claim 9 , wherein the second protective film is a retardation film.

11. An optical display device comprising the polarizing plate according to claim 1.

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