TW201803923A - Polarizing plate and optical display device comprising the same - Google Patents

Abstract

Disclosed are a polarizing plate including a polarizer; and a first protection film formed on at least one surface of the polarizer, wherein the first protection film includes a uniaxially drawn film and an ultraviolet light absorber, and wherein an angle between an absorption axis of the polarizer and a uniaxial drawing direction of the first protection film is between 83 DEG and 97 DEG, and an optical display device including the same.

Description

Polarizing plate and optical display device including the same

The present invention relates to a polarizing plate and an optical display device including the same.

In order to visualize the display pattern of the liquid crystal display device, a polarizing plate is used on the upper surface and the lower surface of the liquid crystal panel for the purpose of controlling the oscillation direction of light. The polarizing plate includes a polarizer and a protective film formed on at least one surface of the polarizer. Triacetyl cellulose (TAC) films are generally used as protective films, but TAC films are more expensive than typical polymer films. Therefore, instead of TAC, inexpensive polymer films such as polyester films (including polyethylene terephthalate (PET) films) or (meth) acrylate films (including polymethacrylate (PMMA) films) are used. membrane.

Liquid crystal in a liquid crystal display device may be damaged by ultraviolet (UV) rays. The ultraviolet rays emitted from the backlight unit of the liquid crystal display device may deform the polarizer in the polarizing plate. Adding an ultraviolet absorber to a protective film in a polarizing plate can reduce ultraviolet transmittance.

Among the ultraviolet absorbers, an ultraviolet absorber that absorbs light having a wavelength of 380 nm or less is generally colored, for example, light yellow. If an excessive amount of an ultraviolet absorber is contained in the protective film, the protective film may exhibit color. This can increase the color value of the polarizing plate, which may not be suitable for applying the polarizing plate to a liquid crystal display device. Therefore, there is a need for a polarizing plate that contains a small amount of an ultraviolet absorber and has a high ultraviolet absorption rate in order to improve ultraviolet light reduction performance and minimize degradation of color values of a protective film.

BACKGROUND ART It is disclosed in Korean Patent Publication No. 2011-14515.

The embodiment relates to a polarizing plate including a protective film which has a small amount of ultraviolet (UV) ray absorber but has a high ultraviolet absorbing property.

Embodiments relate to a polarizing plate including a protective film having excellent ultraviolet light reduction performance and minimizing color value degradation.

The embodiment may be implemented by providing a polarizing plate, which includes: a polarizer; and a first protective film formed on at least one surface of the polarizer. The first protective film may include a uniaxially stretched film and an ultraviolet absorber, and an angle between an absorption axis of the polarizer and a uniaxially stretched direction of the first protective film may be between 83 ° and 97 ° between.

The embodiment can be implemented by providing a liquid crystal display device including the polarizing plate according to the embodiment.

The polarizing plate according to the embodiment may include a protective film having a small amount of an ultraviolet absorber but having a high ultraviolet absorbing property.

The polarizing plate according to the embodiment may include a protective film having excellent ultraviolet light reduction performance and minimizing color value degradation.

Exemplary embodiments will now be explained more fully below with reference to the accompanying drawings; however, the exemplary embodiments may be implemented in different forms and should not be construed as being limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey exemplary implementations to those skilled in the art.

In the drawings, the dimensions of layers and regions may be exaggerated for clarity of illustration. It will also be understood that when a layer or element is referred to as being "on" another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may also be present. In addition, it should also be understood that when a layer is referred to as being "between" two layers, the layer can be the only layer between the two layers, or one or more intervening layers can also be present. Floor. The same reference numbers refer to the same elements throughout.

Various terms are defined throughout this specification, and the meaning of any particular term will be understood in the context of this entire document, except in the context of specific descriptions or uses given in specific cases as set forth below. .

Terms such as "upper surface" and "lower surface" used herein are defined with reference to the drawings. Therefore, it should be understood that the term "upper surface" can be used interchangeably with the term "lower surface" when viewed from different angles, and vice versa.

Unless specifically mentioned, "nx", "ny", and "nz" described herein are three-dimensional coordinate systems (x-axis direction, y-axis direction, and z-axis) of the film at a wavelength of 550 nm, respectively. Direction (thickness direction)). For example, "x-axis direction" may be "machine direction (MD)", and "y-axis direction" may be "transverse direction (TD)".

The polarizing plate according to the embodiment is explained with reference to FIG. 1. FIG. 1 illustrates an exploded perspective view of a polarizing plate according to an embodiment.

1, in an embodiment, a polarizing plate 100 according to an embodiment may include: a polarizer 110; a first protective film 120 formed on a first surface (eg, an upper surface) of the polarizer 110; and a second The protective film 130 is formed on the second surface (for example, on the lower surface) of the polarizer 110.

The first protective film 120 may be a uniaxially stretched film, and an angle A between the absorption axis 110 a of the polarizer 110 and the uniaxially stretched direction 120 a of the first protective film 120 may be between 83 ° and 97 °. Within this range, the transmittance of the polarizing plate 100 for light having a wavelength of 380 nm or less is greatly reduced. In addition, by including even a small amount of an ultraviolet (UV) ray absorber, the transmittance to light having a wavelength of 380 nm or less is maintained, so that the first protective film 120 can be reduced by the presence of the ultraviolet absorber Color performance. For example, the polarizing plate 100 may have 2% or less than 2%, such as 0% to 2%, specifically 1% or less than 1%, such as 0% to light for a wavelength of 380 nm or less. 1% transmittance.

The polarizer 110 can polarize light transmitted through the second protective film 130.

The polarizer 110 may include a polyvinyl alcohol-based film, and there is no limitation on a method of forming the polarizer 110 as long as a polyvinyl alcohol-based film is used. For example, the polarizer 110 may include a modified polyvinyl alcohol film, such as a partially methylated polyvinyl alcohol film, an acetoacetic acid modified polyvinyl alcohol film, and the like. Specifically, the polarizer 110 may be formed by dyeing a polyvinyl alcohol film with iodine or a dichroic dye, and then stretching the polyvinyl alcohol film in a specific direction (for example, a longitudinal direction (MD)). For example, the polarizer 110 may be formed through swelling, dyeing, and stretching steps. The method of performing each step is known in the art. In this case, the absorption axis 110a of the polarizer 110 is substantially parallel to the longitudinal direction. The term "substantially parallel" means that the angle between the absorption axis 110a and the longitudinal direction of the polarizer 110 is between 0 ° and 7 °, which can be regarded as parallel and there is a small error. The polarizer 110 may have a thickness of 3 nm to 30 nm, specifically 10 nm to 20 nm. Within this thickness range, the polarizer 110 may be used in the polarizing plate 100.

In an embodiment, the first protective film 120 may be formed on the upper surface of the polarizer 110 to protect the polarizer 110 and may provide additional functions to the polarizing plate 100.

The first protective film 120 may include an ultraviolet absorber. The first protective film 120 can improve the reliability of the polarizer 110 by absorbing ultraviolet rays transmitted through the polarizer 110 from a backlight unit or the like. The first protective film 120 containing an ultraviolet absorber can also prevent a display unit such as a liquid crystal from being deteriorated by external ultraviolet rays. The ultraviolet absorber can absorb light having a wavelength of 380 nm or less, specifically 200 nm to 380 nm. The ultraviolet absorbent may include an absorbent that absorbs light having a wavelength of 380 nm or less. For example, the ultraviolet absorbent may include an ultraviolet absorbent, such as a colored ultraviolet absorbent, including at least one of a triazine, phenol, benzotriazole, salicylic acid, benzophenone, and humoxamine-based absorbent . Generally, an ultraviolet absorber that absorbs light having a wavelength of 380 nm or less has a light yellow color and can exhibit color to the first protective film 120, which may affect the polarizing plate. The ultraviolet absorber according to the embodiment of the present invention can greatly reduce the transmittance of ultraviolet rays in the polarizing plate 100, and can maintain the transmittance to light having a wavelength of 380 nm even if a smaller amount is used. This can reduce the coloring effect of the ultraviolet absorber on the first protective film 120. The first protective film 120 may include 1% by weight or less, specifically, more than 0% by weight and 1% by weight or less of an ultraviolet absorber. Within this range, the transmittance of ultraviolet rays can be reduced.

The first protective film 120 may include an optically transparent resin. For example, the first protective film 120 may include at least one of the following: non-cellulose, including triethyl cellulose, and the like; polyester, including polyethylene terephthalate, polybutylene terephthalate, Polyethylene naphthalate, polybutylene naphthalate, etc .; cyclic polyolefins, including amorphous cyclic olefin polymers; COP; polycarbonate; polyether fluorene; polyfluorene; polyfluorene; polyfluorene; Acyclic polyolefins; polyacrylates, including polymethacrylates; polyvinyl alcohol; polyvinyl chloride; and polyvinylidene chloride resins. For example, the first protective film 120 may be a polyester resin, more specifically, a polyethylene terephthalate resin, which maintains low moisture permeability and increases reliability.

The first protective film 120 may be a uniaxially stretched film in a transverse direction (TD). Specifically, the first protective film 120 may be a film formed by extruding a resin containing an ultraviolet absorber and then performing uniaxial stretching in the lateral direction. If the first protective film 120 is formed by extruding a resin containing an ultraviolet absorber and then performing uniaxial stretching in the lateral direction, and the absorption axis 110a of the polarizer 110 and the stretching axis 120a of the first protective film 120 ( The angle between them (horizontal) is 83 ° to 97 °, then the polarizing plate 100 according to the embodiment can have the above-mentioned effects, which has been confirmed by the inventors.

In the first protective film 120, at a wavelength of 380 nm, the absorption axis of a standard polarizer having a degree of polarization of 99.99% when mounted in an optical display device (for example, V-7100) for measuring transmittance and The transmittance B (%) when the angle between the lateral directions of the first protective film 120 is 0 °, and the angle between the absorption axis of a standard polarizer with a polarization degree of 99.99% and the lateral direction of the first protective film 120 is The ratio (B / A) of the transmittance A (%) at 90 ° may be 1.1 to 30, specifically 5 to 15. Within this range, the ultraviolet transmittance in the first protective film 120 can be reduced.

When the angle A between the absorption axis 110a of the polarizer 110 and the uniaxial stretching direction 120a of the first protective film 120 is 45 °, the first protective film 120 may have 2% to 5 for light having a wavelength of 380 nm. %, Specifically 2% to 4% transmittance. When the angle A between the absorption axis 110a of the polarizer 110 and the uniaxial stretching direction 120a of the first protective film 120 is 0 °, the first protective film 120 may have 5% to 10 for light having a wavelength of 380 nm. %, Specifically 6% to 8% transmittance. Within this range, the ultraviolet transmittance in the first protective film 120 can be increased.

The first protective film 120 may have an ultra-high delay by stretching it at a high stretching ratio, so that the first protective film 120 may be used when the polarizing plate 100 is incorporated into a liquid crystal display (LCD) device. Reduce the occurrence of rainbow spots to prevent image quality degradation. For example, the first protective film 120 may have 6,000 nm or more at a wavelength of 550 nm, specifically 8,000 nm or more, more specifically 8,000 nm to 12,000 nm, or even More specifically, the in-plane retardation (Re) of 10,100 nm to 12,000 nm is represented by Equation 1. Within this range, when the first protective film 120 is used in the polarizer 110, the generation of rainbow dots can be reduced. In addition, the first protective film 120 can suppress the occurrence of light leakage from the side, and further reduce the variation of the retardation according to the incident angle, thereby preventing the difference between the retardations from increasing.

[Equation 1] Re = (nx-ny) × d where nx and ny are the refractive indexes of the first protective film in the x-axis direction and the y-axis direction at a wavelength of 550 nm, respectively, and d is the first protective film Thickness in nanometers.

The first protective film 120 may have a biaxiality (NZ) of 1.8 or less, specifically 1.0 to 1.8, at a wavelength of 550 nm, as represented by Equation 2. Within this range, the first protective film 120 may have an effect of controlling a rainbow point due to birefringence.

[Equation 2] NZ = (nx-nz) / (nx-ny) where nx, ny, and nz are the first protective film in the x-axis direction, y-axis direction, and z-axis direction at a wavelength of 550 nm, respectively. On the refractive index.

The first protective film 120 may have an out-of-plane retardation (Rth) of 15,000 nm or less, specifically 8,000 nm to 13,000 nm at a wavelength of 550 nm, as represented by Equation 3. Within this range, the first protective film 120 can reduce dots due to birefringence.

[Equation 3] Rth = ((nx + ny) / 2- nz) × d where nx, ny, and nz are the first protective film in the x-axis direction, the y-axis direction, and z at a wavelength of 550 nm, respectively. The refractive index in the axial direction, and d is the thickness of the first protective film, and its unit is nanometer.

The first protective film 120 is easy to crystallize when stretched, and thus may cause rainbow dots when used in a polarizing plate, which results in deterioration of image quality. When both nx and ny are less than 1.65, or both nx and ny are 1.65 or more than 1.65, the first protective film 120 may cause rainbow dots due to birefringence, which is due to the delay according to the incident angle and the wavelength of light Changes. Therefore, in the embodiment, in the first protective film 120, at least one of nx and ny is 1.65 or more than 1.65 to reduce the occurrence of rainbow dots. In some embodiments, nx of the first protective film 120 may be 1.65 or more, such as 1.67 to 1.75, and ny of the first protective film 120 may be less than 1.65, such as 1.45 to 1.60. In some embodiments, the ny of the first protective film 120 may be 1.65 or more, such as 1.67 to 1.72, more specifically 1.69 to 1.72, and the nx of the first protective film 120 may be less than 1.65, such as 1.45. To 1.60. When the absolute value of the difference between nx and ny (| nx-ny |) is 0.1 to 0.2, for example, 0.1 to 0.18, the viewing angle can be further enhanced while reducing the generation of rainbow points. In some embodiments, the absolute value of the difference between nx and ny (| nx-ny |) may be 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, or 0.18. Furthermore, the absolute value of the difference between nx and ny (| nx-ny |) may be between any of these values and any other of these values.

The first protective film 120 may be prepared by performing uniaxial stretching only in a lateral direction without performing longitudinal stretching. The first protective film 120 may have a lateral stretching ratio of 2 to 10 and a longitudinal stretching ratio of 1 to 1.1. As used herein, the term "longitudinal stretching ratio of 1 to 1.1" means that when the film is stretched while being transferred in the longitudinal direction, there is no additional stretching process except that the film is inevitably stretched due to the mechanical movement of the film. status. Specifically, the term "stretching ratio of 1" means a non-stretched state. The term “stretching ratio” used in the first protective film 120 may refer to a ratio of a length of the film after stretching to a length of the film before stretching.

If the lateral stretching ratio is less than 2, the first protective film 120 may have a low retardation, so that the first protective film 120 may appear rainbow dots when applied to a liquid crystal display device, and may be easily deteriorated by the physical properties of the film. Torn. On the other hand, if the lateral stretching ratio is greater than 10, the first protective film 120 may be broken during the stretching process. For example, the transverse stretching ratio may be 3 to 8. Stretching can be performed using at least one of dry stretching and wet stretching. The stretching temperature may be between (Tg-20) ° C and (Tg + 50) ° C based on the Tg (glass transition temperature) of the first protective film 120. Specifically, the stretching temperature may be between 70 ° C and 150 ° C, more specifically between 80 ° C and 130 ° C, and even more specifically between 90 ° C and 120 ° C.

The method may further include thermally stabilizing the stretched first protective film 120. The first protective film 120 stretched at a high stretch ratio often has a restoring force that restores the film to its original state. The thermal stabilization step may control the stress on the restoring force of the first protective film 120, thereby maintaining the thermal stabilization of the film. The thermal stabilization step may include heating the stretched first protective film 120 while fixing both lateral ends of the first protective film 120 and moving the first protective film 120 in the longitudinal direction. Here, the first protective film 120 is stretched in the lateral direction at a stretching ratio that is relatively lower than the stretching step described above. The transverse stretching ratio may be greater than 0 to 3 or less, specifically 0.1 to 2, more specifically 0.1 to 1. The fixing of the first protective film 120 in the lateral direction may be performed just enough to prevent the film from recovering due to a high stretching ratio, and there may be no substantial lateral stretching effect (tension-relaxation) on the first protective film 120. The heating in the heat stabilization step may be performed at 100 ° C to 300 ° C for 1 second to 2 hours.

The first protective film 120 may have a thickness of 50 to 300 micrometers, specifically 50 to 200 micrometers. Within this thickness range of the first protective film 120, the first protective film 120 may be applied to the polarizing plate 100.

Although not shown in FIG. 1, the first protective film 120 may include a functional coating (for example, a hard coating, an anti-reflective layer, or an anti-fingerprint layer) formed on an upper surface thereof to give the polarizing plate 100 an additional Functions. The functional layer may have a thickness of 1 to 10 micrometers. Within this thickness range of the functional layer, the first protective film 120 may be stacked on the polarizer 110 and applied to the polarizing plate 100.

In addition, although not shown in FIG. 1, the first protective film 120 may further include a surface coating layer on a lower surface thereof. When the first protective film 120 is a polyester film, it may have a hydrophobic surface, and the polyethylene terephthalate film may exhibit higher hydrophobicity when used as a protective film. In order to use such a film in the polarizing plate 100, the film may need to be surface-modified to convert a hydrophobic surface to a hydrophilic surface. Surface modification using sodium hydroxide (this is used in typical cellulose based films) may provide insufficient modification or may damage the surface of the film. Therefore, a surface coating layer including a primer having both a hydrophobic functional group and a hydrophilic functional group can be formed on the first protective film 120. The primer having both a hydrophobic functional group and a hydrophilic functional group may include a polyester resin, a polyvinyl acetate resin, and a combination thereof, but is not limited thereto. The surface coating can improve the mechanical properties of the first protective film 120 and help reduce the moisture permeability of the first protective film 120, so that the polarizing plate 100 can exhibit high resistance to several external conditions. In addition, a surface coating layer may be formed between the first protective film 120 and the polarizing plate 100 to improve the adhesion between the first protective film 120 and the polarizer 110.

The second protective film 130 may be formed on a lower surface of the polarizer 110 to impart mechanical strength to the polarizing plate 100 and protect the polarizer 110.

The second protective film 130 may be formed on one surface of the liquid crystal display panel, and may have a retardation value within a specified range to compensate a viewing angle. For example, the second protective film 130 may have an in-plane retardation (Re) of 40 nm to 60 nm at a wavelength of 550 nm. Within this in-plane retardation range, the second protective film 130 can provide improved image quality. In some embodiments, the second protective film 130 may have a thickness of 25 micrometers to 500 micrometers, more specifically 25 micrometers to 50 micrometers. Within this thickness range, the second protective film 130 may be used in the polarizing plate 100.

The second protective film 130 may include a polyester film (including polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, etc.) or a non- Transparent optical film of polyester film. The non-polyester film may include at least one of the following: cellulose (including triethylammonium cellulose, etc.), cyclic polyolefin, polycarbonate, polyetherammonium, polyammonium, polyammonium, polyimide, polyimide Olefins, polyacrylates, polyvinyl alcohol, polyvinyl chloride, and / or polyvinylidene chloride resins.

The polarizing plate 100 may have a thickness of 25 to 500 microns. Within this range, the polarizing plate 100 may be used in a liquid crystal display. The polarizing plate 100 may have a polarization degree of 99.99% or more, such as 99.99% to 99.999%, and 40% or more, such as 40% to 80% (for example, in the visible spectrum (for example, 550 nm) Measurement). Within these ranges, the polarizing plate 100 does not show deterioration in optical properties when mounted on a liquid crystal display.

Although not shown in FIG. 1, a bonding layer may be formed between the polarizer 110 and the first protective film 120 and between the polarizer 110 and the second protective film 130. The bonding layer may include any suitable adhesive, such as at least one of an aqueous adhesive, a pressure-sensitive adhesive, and / or a photo-curable adhesive. In addition, although not shown in FIG. 1, an adhesive layer may be further formed on the lower surface of the second protective film 130 to stack the polarizing plate 100 on the liquid crystal display panel. For example, the adhesive layer may include, but is not limited to, a pressure-sensitive adhesive.

An optical display device according to an embodiment of the present invention may include a liquid crystal display device including the above-mentioned polarizing plate. The liquid crystal display device may include a liquid crystal display panel, a first polarizing plate provided on an upper surface of the liquid crystal display panel, a backlight unit provided on a lower surface of the liquid crystal display panel, and a lower portion of the liquid crystal display panel. A second polarizing plate between the surface and the backlight unit. The first polarizing plate may include a polarizing plate according to an embodiment of the present invention.

The liquid crystal display panel may include a panel including a liquid crystal cell layer embedded between a first substrate and a second substrate. In some embodiments, the first substrate may be a color filter (CF) substrate (upper substrate), and the second substrate may be a thin film transistor (TFT) substrate (lower substrate). The first substrate and the second substrate may be formed of the same or different materials, and may be, for example, a glass substrate or a plastic substrate. The plastic substrate may be formed of any plastic material that can be applied to a flexible display, such as polyethylene terephthalate (PET), polycarbonate (PC), polyimide (PI), polyethylene naphthalate Esters (PEN), polyethers (PES), polyacrylates (PAR), and cyclic olefin copolymers (COC), but not limited to this. The liquid crystal cell layer may include a vertical alignment (VA) mode, an in-plane switching (IPS) mode, a fringe field switching (FFS) mode, or a twisted nematic (TN) mode. ) Mode arranged liquid crystal.

The second polarizing plate may include a polarizing plate commonly used in the art.

A backlight unit well known in the field of liquid crystal displays can be used, and the backlight unit may include a light source member, a light guide plate, a reflection plate, a diffusion plate, and the like.

Next, the present invention will be explained in more detail with reference to some examples. It should be understood, however, that these examples are provided for illustrative purposes only and should not be construed as limiting the invention in any way. The following examples and comparative examples are provided in order to highlight the characteristics of one or more embodiments, but it should be understood that the examples and comparative examples should not be interpreted as limiting the scope of the examples, nor should the comparative examples be interpreted as being within the scope of the examples other than. In addition, it should be understood that the examples are not limited to the specific details described in the examples and comparative examples.

Example 1

A polarizer was prepared by stretching a polyvinyl alcohol film VF-PS6000 (Kuraray Co., Ltd., thickness: 60 microns) at 60 ° C. to a stretching ratio of 3, Iodine was then adsorbed and stretched to a draw ratio of 2.5 in a boric acid aqueous solution at 40 ° C.

While using a roller to mechanically transfer the film in the longitudinal direction, a polyethylene terephthalate (PET) resin and a composition including CGX UVA 006 (BASF Corporation) as an ultraviolet absorbent (in the composition 1% by weight of UV absorber is included therein) subjected to melt extrusion and stretched only in the transverse direction to have a stretch ratio of 6 (without longitudinal stretching), and then tensioned-relaxed at 100 ° C Thus, a polyethylene terephthalate (PET) film 1 was prepared.

The thickness of the PET film 1 is 80 micrometers. In the PET film 1 used as the first protective film, Re of Equation 1 is 8,000 nm, NZ of Equation 2 is 1.6, and Rth of Equation 3 is 9,600 nm. Re, NZ, and Rth are measured at a wavelength of 550 nanometers using a delay measurement device Axoscan (Axometrics, Inc.).

The detailed properties of the PET film 1 are shown in Table 1.

When measured by CM-3600D (Konica Minolta, Inc.), when using D1925 light source, PET film 1 has a color value of Yellow Index (YI) of 1.8, and D65 is used. For light source, a * is -0.1 and & b * is 0.9. The PET film 1 was inserted into a UV-VIS spectrometer V-7100 (Jasco Incorporated). As shown in Table 1, the angle B (°) between the absorption axis of a standard polarizer with a polarization degree of 99.99% and the lateral direction of the PET film 1 installed in the UV-visible spectrometer V-7100 was changed. The transmission at a wavelength of 380 nm to 800 nm, the transmission at a wavelength of 380 nm when measured in the longitudinal direction, and the transmission at a wavelength of 380 nm when measured in the lateral direction were measured. rate. Transmission has been measured since then at a wavelength of 380 nm. When measuring the transmittance, the color values "as" and "bs" were also obtained from the UV-visible spectrometer V-7100, and the results are shown in Table 1.

The triacetylene cellulose film KC4DR-1 (Konica Co., Ltd., thickness: 40 microns) was bonded to the first surface of the polarizer prepared above, and the adhesive Z-200 ( Nippon Goshei) bonded a PET film 1 having an angle A (°) shown in Table 2 to the second surface of the polarizer to prepare a polarizing plate. The angle A is defined as the angle between the absorption axis of the polarizer and the uniaxial stretching direction (lateral direction) of the PET film 1.

Example 2

A polarizing plate of Example 2 was prepared in the same manner as in Example 1 except that the angle A (°) was changed as shown in Table 2.

Example 3

A polarizing plate of Example 3 was prepared in the same manner as in Example 1 except that the angle A (°) was changed as shown in Table 2.

Comparative Example 1 and Comparative Example 2

The polarizing plates of Comparative Example 1 and Comparative Example 2 were prepared in the same manner as in Example 1 except that the angle A (°) was changed as shown in Table 2.

Comparative Example 3

In addition to the use of TAC film KC4DR-1 (Konica Co., Ltd., thickness: 40 microns, containing triazine as a UV absorber, 1% by weight of UV absorber in the composition of the TAC film, non-stretch film) instead of PET Except for the film 1, a polarizing plate of Comparative Example 3 was prepared in the same manner as in Example 1. Since the TAC film does not need to be stretched, the angle A (°) is uncertain.

The properties of the TAC film were measured in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 4

The polyethylene terephthalate (PET) resin of Example 1 and a composition containing Tinuvin 326 (Ciba Specialty Chemicals, Inc.) were used as a composition for ultraviolet absorbers (in The composition contains 1% by weight of an ultraviolet absorber) subjected to melt extrusion, and biaxially stretched to a stretch ratio of 3 in the longitudinal direction and a stretch ratio of 3 in the transverse direction, thereby A polyethylene terephthalate (PET) film 2 (thickness: 40 microns) was prepared.

A polarizing plate of Comparative Example 4 was prepared in the same manner as in Example 1 except that the PET film 2 was used instead of the PET film 1. Since the PET film 2 is biaxially stretched, the angle A (°) cannot be fixed.

The properties of the PET film 2 were measured in the same manner as in Example 1, and the results are shown in Table 1.

Table 1

The physical properties of each of the polarizers prepared in Examples 1 to 3 and Comparative Examples 1 to 4 were evaluated, and the results are shown in Table 2.

* Optical properties and color values: UV-Vis spectrometer V-7100 (Japan Spectroscopy Corporation) was used to irradiate light with a wavelength of 380 nm or light with a wavelength of 380 nm to 800 nm to Examples 1 to 3 and Each of the polarizers prepared in Comparative Examples 1 to 4 was such that light was transmitted from the second protective film to the first protective film.

Table 2

As shown in Table 2, even if the polarizer according to the embodiment of the present invention contains a small amount of an ultraviolet absorber, the polarizer still has a high ultraviolet reduction performance.

Exemplary embodiments have been disclosed herein and, although specific terms are used, these specific terms should be used and interpreted to have a general and illustrative meaning only and not for limiting purposes. In some cases, as would be apparent to one of ordinary skill in the art before the application is filed, the features, characteristics, and / or elements described in connection with the specific embodiments may be used alone, unless specifically stated otherwise Or in combination with the features, characteristics, and / or elements described in connection with other embodiments. Therefore, those skilled in the art should understand that various changes in form and details can be made thereto without departing from the spirit and scope of the invention as described in the above claims.

100‧‧‧ polarizing plate
110‧‧‧Polarizer
110a‧‧‧ polarizer absorption axis
120‧‧‧first protective film
120a‧‧‧First protective film uniaxial stretching direction / axial axis
130‧‧‧Second protective film
A‧‧‧ angle

FIG. 1 illustrates an exploded perspective view of a polarizing plate according to an embodiment.

100‧‧‧ polarizing plate

110‧‧‧Polarizer

110a‧‧‧ polarizer absorption axis

120‧‧‧first protective film

120a‧‧‧First protective film uniaxial stretching direction / axial axis

130‧‧‧Second protective film

A‧‧‧ angle

Claims (11)

A polarizing plate includes: a polarizer; and a first protective film formed on at least one surface of the polarizer, wherein the first protective film includes a uniaxially stretched film and an ultraviolet absorber, and wherein The angle between the absorption axis of the polarizer and the uniaxial stretching direction of the first protective film is between 83 ° and 97 °. The polarizing plate according to item 1 of the scope of patent application, wherein the ultraviolet absorber absorbs light having a wavelength of 380 nm or less. The polarizing plate according to item 1 of the scope of patent application, wherein the ultraviolet absorber includes at least one of the following: triazine, phenol, benzotriazole, salicylic acid, benzophenone, and humoxamine Absorbent. The polarizing plate according to item 1 of the scope of patent application, wherein the ultraviolet absorber is present in the first protective film in an amount of 1% by weight or less. The polarizing plate according to item 1 of the scope of patent application, wherein the first protective film includes a resin film containing the ultraviolet absorber and uniaxially stretched in a transverse direction (TD). The polarizing plate according to item 1 of the scope of patent application, wherein in the first protective film, at a wavelength of 380 nm, the absorption axis of a standard polarizer with a polarization degree of 99.99% and the first protection The angle between the transverse direction (TD) of the film is 0 ° and the transmission rate B (%) between the absorption axis of the standard polarizer when the polarization is 99.99% and the transverse direction (TD) of the first protective film The ratio (B / A) of the transmittance A (%) at an angle of 90 ° is 1.1 to 30. The polarizing plate according to item 1 of the scope of patent application, wherein when an angle between the absorption axis of the polarizer and the uniaxial stretching direction of the first protective film is 45 °, the The first protective film has a transmittance of 2% to 5% for light having a wavelength of 380 nm or less. The polarizing plate as described in claim 1, wherein when the angle between the absorption axis of the polarizer and the uniaxial stretching direction of the first protective film is 0 °, the The first protective film has a transmittance of 5% to 10% for light having a wavelength of 380 nm or less. The polarizing plate as described in claim 1, wherein the first protective film includes a non-cellulose film. The polarizing plate as described in claim 1, wherein the first protective film is formed on one surface of the polarizer, and the second protective film is formed on the other surface of the polarizer. An optical display device, comprising the polarizing plate according to any one of items 1 to 10 of the patent scope.