TW201400934A - Polarizing plate and liquid crystal comprising the same display - Google Patents

Abstract

The present invention relates to a polarization plate and to a liquid crystal display device comprising same. More particularly, the polarization plate comprises a first protective film, a polarizer, a second protective film, and an adhesive layer stacked in the abovementioned order. The first protective film or the first and second protective films extend in a machine direction (MD), and have a front phase difference value (RO) of 300 nm or higher. The above-described polarization plate is used as a polarization plate for a liquid crystal display device, in which the protective film is inexpensive and has a high phase difference. Therefore, excellent price competitiveness can be achieved and rainbow discoloration, which might otherwise be caused by the first protective film, can be suppressed so as to maintain the quality of an image (e.g., to ensure a viewing angle).

Description

Polarizing plate and liquid crystal display device having polarizing plate

The present invention relates to a polarizing plate which can suppress the generation of rainbow spots when a protective film having a high phase difference is used, and a liquid crystal display device including the polarizing plate.

Liquid crystal display (LCD) is the most popular market share in flat panel displays and is used to replace the most popular cathode ray tube (CRT) in image display devices.

The liquid crystal display device has greatly improved various technical problems in the initial development stage, and is now also working to increase price competitiveness to expand market share. Thus, an attempt was made to improve a polarizing plate which constitutes a core component of a liquid crystal display device.

A representative method of increasing the price competitiveness of polarizing plates is to use an inexpensive polarizer protective film.

The main purpose of the polarizer protective film is to protect the polarizer with weak mechanical strength. Recently, if the protective film is stacked on the side surface of the liquid crystal panel of the polarizer, it is possible to impart an appropriate phase difference by stretching and to add a viewing angle compensation function. The phase difference value of the protective film stacked on the other side of the liquid crystal panel of the polarizer is not Affected by optical characteristics, this is a common understanding of engineers in the field of technology.

In the protective film, triacetate cellulose (TAC) or the like is used as a representative. The cellulose triacetate film (TAC) is generally produced by casting, and a negative C plate is formed while volatilizing the solvent. The price of this cellulose triacetate film (TAC) is much higher than that of a general plastic film.

Therefore, it has been attempted to replace the cellulose triacetate film (TAC) with a plastic film having a lower unit price as a protective film.

However, most of the low-priced plastic films are stretched at a high magnification in order to increase the yield so that the phase difference is increased, and the liquid crystal display device in which the protective film is stacked has the disadvantage of generating rainbow spots and reducing image quality.

Further, a method for suppressing the generation of rainbow spots by a film which is stretched at a high magnification is disclosed in which a film which is stretched on a high-magnification film is applied with a dispersing agent or a film which is stretched at a high rate. However, in this case, there is also a problem that image quality is deteriorated or manufacturing cost is increased.

SUMMARY OF THE INVENTION An object of the present invention is to provide a polarizing plate which does not degrade image quality and which uses a protective film having a low-cost type and high phase difference.

Another object of the present invention is to provide a liquid crystal display device including the polarizing plate.

In order to achieve the above object, the present invention provides a polarizing plate in which a first protective film, a polarizing film, a second protective film, and an adhesive layer are sequentially stacked, and the first protective film is uniaxially oriented in the MD direction (Machine Direction). The tensile and frontal retardation value (R0) is 300 nm or more.

The first protective film may have a front retardation value (R0) of 500 nm or more.

In addition, the present invention provides a polarizing plate in which a first protective film, a polarizing film, a second protective film, and an adhesive layer are sequentially stacked, and the first protective film and the second protective film are separately uniaxially pulled in the MD direction. The front surface retardation (R0) is 300 nm or more.

The first protective film and the second protective film may each have a front surface retardation value (R0) of 500 nm or more.

The first protective film may have a refractive index ratio (NZ) of 0 ≦ NZ ≦ 1.

The first protective film preferably has a refractive index ratio (NZ) of 0 or 1.

The first protective film may be a cycloolefin polymer (COP), a cycloolefin copolymer (COC), a polyethylene terephthalate (PET), or a polypropylene (PP). , at least one selected from the group consisting of polycarbonate (PC), polystyrene (PS), polysulfone (PSF), and polymethyl methacrylate (PMMA) .

The first protective film and the polarizer are bonded to each other on the opposite side, and the bread contains a surface treatment layer.

The second protective film may have a refractive index ratio (NZ) of 0 or 1.

The second protective film may be a cycloolefin polymer (COP), a cycloolefin copolymer (COC), a polyethylene terephthalate (PET), or a polypropylene (PP). , at least one selected from the group consisting of polycarbonate (PC), polystyrene (PS), polysulfone (PSF), and polymethyl methacrylate (PMMA) .

Further, the present invention provides a liquid crystal display device including a polarizing plate.

The backlight of the liquid crystal display device can be a polarized backlight.

When the polarizing plate of the present invention is applied to a liquid crystal display device, it is not only used because of the use of a low-cost type high phase difference protective film, but also has a better price competitiveness, and can suppress a rainbow spot generated by the protective film having the high phase difference to maintain the image. The effect of quality (ensure perspective, etc.).

Fig. 1 is a vertical sectional view showing a polarizing plate of the present invention.

Fig. 2 is a view showing the configuration of a liquid crystal display device of a first embodiment of the present invention.

Figure 3 is a view showing the liquid crystal display device of the first embodiment of the present invention, when applied with voltage, from all directions Transmissive characteristics.

Fig. 4 is a view showing the transmission characteristics from the respective directions when a voltage is applied to the liquid crystal display device of the second embodiment of the present invention.

Fig. 5 is a view showing the transmission characteristics from the respective directions when a voltage is applied to the liquid crystal display device of the third embodiment of the present invention.

Fig. 6 is a view showing the transmission characteristics from the respective directions when a voltage is applied to the liquid crystal display device of the fourth embodiment of the present invention.

Fig. 7 is a view showing the transmission characteristics from the respective directions when a voltage is applied to the liquid crystal display device of the fifth embodiment of the present invention.

Fig. 8 is a view showing the transmission characteristics from the respective directions when a voltage is applied to the liquid crystal display device of the sixth embodiment of the present invention.

Fig. 9 is a view showing the transmission characteristics from the respective directions when a voltage is applied to the liquid crystal display device of the seventh embodiment of the present invention.

Fig. 10 is a view showing the transmission characteristics from the respective directions when a voltage is applied to the liquid crystal display device of the eighth embodiment of the present invention.

Fig. 11 is a view showing the transmission characteristics from the respective directions when a voltage is applied to the liquid crystal display device of the ninth embodiment of the present invention.

Fig. 12 is a view showing the transmission characteristics from the respective directions when a voltage is applied to the liquid crystal display device of the tenth embodiment of the present invention.

Fig. 13 is a view showing the transmission characteristics from the respective directions when a voltage is applied to the liquid crystal display device of the eleventh embodiment of the present invention.

Figure 14 is a view showing the liquid crystal display device of the twelfth embodiment of the present invention, when voltage is applied, from various directions Schematic diagram of penetration characteristics.

Fig. 15 is a view showing the transmission characteristics from the respective directions when a voltage is applied to the liquid crystal display device of Comparative Example 1.

Fig. 16 is a view showing the transmission characteristics from the respective directions when a voltage is applied to the liquid crystal display device of Comparative Example 2.

The present invention relates to a polarizing plate which can suppress the generation of rainbow spots when a protective film having a high phase difference is used, and a liquid crystal display device including the polarizing plate.

The phenomenon that the rainbow ray is caused by a large change in the phase difference due to the incident angle when the polarized light passes through the phase difference layer and a large difference in the phase difference due to the wavelength.

In general, a high retardation film is formed by high-magnification stretching, so that the phase difference value is large and the phase difference value due to the incident angle is also large, and therefore, a rainbow spot is generated when the polarized light passes. In addition, most of the films have positive dispersion, so the phase difference generated by the wavelength changes more.

In the present invention, a high retardation film is used as a polarizing plate protective film, but the stretching method and the refractive index ratio of the high retardation film are controlled within a specific range to suppress generation of rainbow spots.

The invention is described in detail below.

The polarizing plate of the present invention is sequentially stacked with a first protective film, a polarizing plate, a second protective film and an adhesive layer. The first protective film is uniaxially stretched in the MD direction, and has a front retardation value (R0) of 300 nm or more, preferably 500 nm or more.

Further, in the polarizing plate of the present invention, the first protective film and the second protective film are uniaxially stretched in the MD direction, respectively, and the front retardation value (R0) is 300 nm or more, preferably 500 nm or more.

In particular, when the liquid crystal cell is in the CCD mode, the FFS mode, the PLS mode, the ADS mode, or the like, and the liquid crystal is in the planar rotation mode, the first protective film and the second protective film are preferably the same.

In general, in the case of producing a film by a stretching process, the more the stretching is performed, the larger the phase difference value is and the lower the manufacturing unit price per unit area of the film. The conventional representative protective film of cellulose triacetate (TAC), if not stretched, the frontal phase difference (R0) is 10 nm or less, and the thickness direction retardation (Rth) shows 30 to 50 nm. Optical properties. This optical property is significantly lower than the average plastic film in the lower phase difference range.

The following formulas 1 to 3 define the front phase difference (R0), the thickness direction retardation (Rth), and the refractive index ratio (NZ) of the optical properties of the first protective film and the second protective film. This optical property is for the full wavelength in the visible light field.

[Formula 1] R0=(Nx-Ny)×d

(where Nx and Ny are plane refractive indices and Nx≧Ny, and d is film thickness.)

[Formula 2] Rth=[(Nx+Ny)/2-Nz]×d

(where Nx and Ny are plane refractive indices and Nx≧Ny, and the Nz-based film has a refractive index in the thickness direction, and d is a film thickness.)

[Formula 3] NZ = (Nx - Nz) / (Nx - Ny) = Rth / R0 + 0.5

(Hx, Ny is a plane refractive index and Nx≧Ny, and the Nz-based film has a refractive index in the thickness direction.)

The present invention does not conventionally limit the phase difference in the optical characteristics of the protective film, but employs a highly stretched film used as a film in the art. The film having a front retardation value (R0) of 300 nm or more is a film which is stretched at a high magnification and has a low optical unit price per unit area of the film.

The first protective film or the first and second protective films must be uniaxially stretched in the MD direction. The MD direction refers to a film in a ROLL state before the bonding sheet is expanded or curled, and uniaxial stretching refers to a film which is stretched and positioned only in a single direction.

When the film is uniaxially stretched in the MD direction, the optical axis extension line does not extend beyond the film surface and is in a plane, so that high phase difference unevenness does not occur.

Further, the first protective film has a refractive index ratio (NZ) of 0 ≦ NZ ≦ 1, and NZ is preferably 0 or 1 in consideration of ease of processing and industrial applicability. If the refractive index ratio (NZ) is less than 0 or exceeds 1, the slope may cause a problem of high phase difference unevenness.

The first protective film may be a cycloolefin polymer (COP), a cycloolefin copolymer (COC), a polyethylene terephthalate (PET), or a polypropylene (PP). , at least one selected from the group consisting of polycarbonate (PC), polystyrene (PS), polysulfone (PSF), and polymethyl methacrylate (PMMA) Use it.

Further, the first protective film and the polarizer may be provided with a surface treatment layer on the opposite side of the side.

The polarizer is an optical film that converts the incident natural light into a desired single polarized state (linear polarized state), and can adsorb and position a dichroic dye on a film composed of a polyvinyl alcohol-based resin.

The polyvinyl alcohol-based resin constituting the polarizer is produced by saponifying a polyvinyl acetate-based resin. For example, a polyvinyl acetate-based resin may be a copolymer of another monomer copolymerizable with vinyl acetate, in addition to vinyl acetate of a homopolymer of vinyl acetate. Specific examples of the other monomer copolymerizable with vinyl acetate include unsaturated carboxylic acids, unsaturated sulfonic acids, olefins, vinyl ethers, and acrylamides having an ammonium salt group. Further, the polyvinyl alcohol-based resin may be a modified product, and for example, polyethylene formaldehyde or polyvinyl acetal modified into an aldehyde may be used. The polyvinyl alcohol-based resin has a degree of saponification of usually 85 to 100 mol%, preferably 98 mol% or more. Another, gather The vinyl alcohol-based resin generally has a polymerization degree of 1,000 to 10,000, preferably 1,500 to 5,000.

This polyvinyl alcohol-based resin was formed into a film and used as a polarizer. The film forming method of the polyvinyl alcohol-based resin is not particularly limited, and various well-known methods can be used. The film thickness of the polyvinyl alcohol-based resin is not particularly limited, and may be, for example, 3 to 150 μm.

The polarizer is generally produced by a process of uniaxially stretching a polyvinyl alcohol-based film, a process of dyeing and adsorbing with a dichroic dye, a process of treating with a boric acid aqueous solution, and a washing and drying process.

The uniaxial stretching of the polyvinyl alcohol-based film can be carried out before dyeing, simultaneously with dyeing, or after dyeing. If uniaxial stretching is performed after dyeing, it can be performed before boric acid treatment or boric acid treatment. It is of course also possible to perform uniaxial stretching in a plurality of stages after the respective works are combined. The uniaxial stretching may use a circumferential speed or a different heating roller, a dry stretching in the atmosphere, or a wet drawing in which the solvent is stretched in an expanded state. Stretch. The stretching ratio is generally 3 to 8 times.

A process of dyeing the stretched polyvinyl alcohol-based film with a dichroic dye, for example, a method of immersing a polyvinyl alcohol-based film in an aqueous solution containing a dichroic dye. As a specific example of the dichroic dye, iodine or a dichroic organic dye can be used. Further, the polyvinyl alcohol-based film is preferably immersed in water to be swollen before being dyed.

When iodine is used as the dichroic dye, generally, a method in which a polyvinyl alcohol-based film is immersed in an aqueous solution for dyeing containing iodine and potassium iodide for dyeing can be used. In general, the iodine content contained in the aqueous solution for dyeing is 0.01 to 1 part by weight based on 100 parts by weight of water (distilled water), and the potassium iodide content is 0.5 to 20 parts by weight based on 100 parts by weight of water. The temperature of the aqueous solution for dyeing is generally 20 to 40 ° C, and the soaking time, for example, the dyeing time is generally 20 to 1,800 seconds.

On the other hand, when a dichroic dye is used as a dichroic dye, in general, a method of dyeing a polyvinyl alcohol-based film in an aqueous solution for dyeing containing a water-soluble dichroic organic dye can be used. The content of the dichroic organic dye contained in the aqueous solution for dyeing is generally 1 × 10 ^-4 to 10 parts by weight, preferably 1 × 10 ^-3 to 1 part by weight, per 100 parts by weight of water. The aqueous solution for dyeing may further contain an inorganic salt such as sodium sulfate as a dyeing auxiliary. The temperature of the aqueous solution for dyeing is generally 20 to 80 ° C, and the soaking time, for example, the dyeing time is generally 10 to 1,800 seconds.

The process of subjecting the dyed polyvinyl alcohol-based film to boric acid treatment can be carried out by immersing it in an aqueous solution containing boric acid. In general, the aqueous solution containing boric acid has a boric acid content of 2 to 15 parts by weight, preferably 5 to 12 parts by weight, per 100 parts by weight of water. When the dichroic dye is an aqueous solution of iodine boric acid, it preferably contains potassium iodide, and the content is usually 0.1 to 15 parts by weight, preferably 5 to 12 parts by weight, per 100 parts by weight of the water system. The temperature of the aqueous solution containing boric acid is 50 ° C or higher, preferably 50 to 85 ° C, more preferably 60 to 80 ° C, and the soaking time is 60 to 1,200 seconds, preferably 150 to 600 seconds, and more preferably 200 to 400. second.

After the boric acid treatment, the polyvinyl alcohol-based film was washed with water and dried. Washing treatment can be treated with boric acid The polyvinyl alcohol film is immersed in water, and the water temperature during the water washing treatment is 5 to 40 ° C, and the soaking time is 1 to 120 seconds. After washing, it is dried to obtain a polarizer. Generally, the drying treatment can be performed by a hot air dryer or a far infrared heater, and the drying treatment temperature is generally 30 to 100 ° C, preferably 50 to 80 ° C, and the drying time is generally 60 to 600 seconds, preferably 120. ~600 seconds.

The thickness of the polarizer can be 3 to 40 μm.

Since the polarizer has a weak mechanical strength, the second protective film serves to protect the film of the polarizer.

The second protective film may be selected depending on the type of resin such as water-vapor permeability, and may be selected depending on transparency, mechanical strength, thermal stability, water repellency, and isotropic properties.

Specifically, polyethylene terephthalate (PET), polyethyleneimine (PEI), polyethylene naphthalate (PEN), polyparaphenylene can be used. Polyester resin such as polybutylene terephthalate (PBT); cellulose resin such as diacetyl cellulose (DAC) or triacetyl cellulose (TAC); polycarbonate resin Acrylic resin such as polymetacrylate or polyethylmethacrylate; styrene such as polystyrene or arylonitrile syrene (AS) copolymer Resin; polyethylene, polypropylene, polyolefin resin having a ring system or a norbornene structure, a polyolefin resin such as an ethylene propylene rubber (ehylene popylene) copolymer; a resin; an amine resin such as nylon or aromatic polyamide; a quinone imine resin; Polyether resin; fluorene resin; polyether ether ketone resin; fluidized polyether ether ketone resin; vinyl alcohol resin; vinyl chloride resin; vinyl butyral resin; aryl resin; A film selected from the group consisting of a formaldehyde resin, a thermoplastic resin such as an epoxy resin, or a film composed of a mixture of the thermoplastic resin may be used. Further, a film composed of a thermosetting resin such as a (meth) acrylate, a urethane, an acrylate, an epoxy or a fluorene, or an ultraviolet curable resin may be used.

In the second protective film, the thermoplastic resin content is 50 to 100% by weight, preferably 50 to 99% by weight, more preferably 60 to 98% by weight, and most preferably 70 to 97% by weight. When the content is less than 50% by weight, it is found that the high transparency of the thermoplastic resin originally is insufficient.

Further, in the present invention, the second protective film is uniaxially stretched in the MD direction and the front retardation value (R0) is 300 nm, and in this case, the refractive index ratio (NZ) is preferably 0 or 1.

If the NZ of the second protective film is 0 or 1, the optical axis can be hidden in the plane of the film and effectively suppress the generation of rainbow spots. At this time, the material of the second protective film is the same as that of the first protective film.

The thickness of the first and second protective films is not particularly limited. However, if the thickness is too small, the strength and workability are lowered. When the thickness is too large, the transparency is lowered or the curing time is prolonged after being stacked on the polarizer. The thickness of the protective film is 5 to 200 μm, preferably 10 to 150 μm, and more preferably 20 to 100 μm.

An adhesive layer is formed between the polarizer and the first protective film and between the polarizer and the second protective film. For example, the adhesive layer may use an aqueous adhesive or a UV hardening type adhesive.

The adhesive agent can fully adhere the polarizer to the protective film. If the optical transparency is good and the yellowing or the like does not change due to time, the type thereof is not particularly limited. For example, it may be a poly An aqueous binder composition of a vinyl alcohol resin and a crosslinking agent.

The polyvinyl alcohol-based resin contained in the aqueous adhesive composition may, for example, be a polyvinyl alcohol-based resin or a polyvinyl alcohol-based resin having an ethyl acetonitrile group, and a polyvinyl alcohol-based resin having an ethyl acetonitrile group. As a polyvinyl alcohol-based adhesive having a highly active functional group, it is preferable to increase the durability of the polarizing plate.

The resin contained in the UV curable adhesive composition is generally used in the art, and an epoxy resin, an acrylic resin or the like can be used.

Further, in order to improve the adhesion of the surface of the polarizer to be bonded to the protective film, surface treatment such as plasma treatment, corona treatment, ultraviolet irradiation treatment, flame treatment or saponification treatment may be appropriately performed.

The method of bonding the protective film to the polarizer through the adhesive can be carried out by a method well known in the art, for example, by a casting method, a wire bar coating, or a gravure coating. A method of applying an adhesive to a polarizer, a protective film, or the entire number of the other surfaces to bond them, such as a die coating method or a spray method. The casting method described herein means that the polarizer or the protective film of the object to be coated is moved in an approximately oblique direction, a horizontal direction, or an oblique direction therebetween, and an adhesive is applied to the surface of the coated object. The method of shed and spread. After the application of the adhesive, the polarizer and the protective film are joined by a bonding roller or the like.

The adhesive layer is a layer for bonding to the liquid crystal cell, and may be formed of an adhesive composition generally used in the art including an adhesive resin and a crosslinking agent.

As the adhesive resin contained in the adhesive composition, an acrylic, an anthraquinone, a rubber, a urethane, a polyester or an epoxy copolymer may be used, and an acrylic copolymer is preferably used. Further, the adhesive composition may include a well-known antistatic agent such as an alkali metal salt, an ionic compound, a conductive polymer, a metal oxide, or a CNT. Among them, it is preferred to contain an ionic oxide.

The method of stacking the adhesive layer on the polarizing plate is not particularly limited as long as it is generally used in the art. For example, the adhesive composition can be applied to the antistatic coating layer formed on the polarizer protective film in the same manner as the coating method of the antistatic agent coating composition, and dried. Stacking. In addition, after forming the adhesive layer on the release film of the silicone coating by the same coating method as described above and forming the adhesive sheet, the antistatic formed by the roller compression device is stacked on the polarizer protective film. On the coating layer. In this case, if the ultraviolet curable compound containing a crosslinking agent is contained in the adhesive composition, it is preferred to irradiate the ultraviolet rays after the application of the adhesive composition or after stacking by a roller compression device.

The thickness of the adhesive layer can be adjusted according to the adhesive force, and is generally preferably from 3 to 100 μm, more preferably from 10 to 100 μm.

The liquid crystal display device of the present invention may be provided with the polarizing plate on the upper side, the lower side, or the upper/lower side. If the polarizing plate is provided on the upper side or the lower side, the other polarizing plate can be used in the art and used in the polarizing plate. It is used in the form of a protective film on both sides.

The preferred embodiments are disclosed to facilitate the understanding of the present invention, but the following examples are merely examples of the present invention, but those of ordinary skill in the art should understand that various changes can be made within the scope and technical scope of the present invention. And the amendments, the relevant variants and amendments shall fall within the scope of the patent application for attachment.

<Example 1>

The measurement data of each optical film, liquid crystal cell and backlight of the present invention is stacked on the TECH WIZ LCD as shown in FIG. The liquid crystal cell of the 55-inch PS-VA mode liquid crystal display device was parameterized on the TECH WIZ LCD and stacked.

The liquid crystal display device is composed of a polarized backlight, a lower polarizing plate PS-VA mode liquid crystal cell, and an upper polarizing plate. The upper and lower polarizers are sequentially stacked on the side of the liquid crystal cell, and the adhesive layer, the second protective film, the adhesive layer, the polarizer, the adhesive layer, and the first protective film are sequentially stacked.

The polarizer is stretched and dyed by PVA to add a polarizer function, and the absorption axis of the backlight side polarizer is stacked in the vertical direction when viewed from the visual side, and the absorption axis of the visual side polarizer is disposed in the horizontal direction. .

The polarizing performance of the polarizer is 139 to 780 nm, and the luminosity factor has a polarization degree of 99.9% or more, and the luminescence factor has a monomer transmittance of 41% or more. The luminosity factor is the polarization ratio and the luminescence factor. The transmittance of the monomer is set to TD(λ) when the wavelength is transmitted through the axis, and the transmittance of the absorption axis is set to MD(λ), JIS Z 8701. : The luminous factor defined in 1999 is set to the compensation value as The time is defined by the following formulas 4-8.

Each of the first protective film on the upper side and the lower side is uniaxially stretched in the MD direction, and a polyterephthalic acid having a front side retardation (R0) of 589 nm and a refractive index ratio (NZ) of 1 is stacked. Pethylethylene terephthalate (PET). The first protective film is stacked perpendicularly to each other with the direction of the absorption axis of the adjacent polarizer and the slow axis.

Each of the second protective film on the upper side and the lower side is provided with a protective film of a phase difference compensation function, and a polycycloolefin having a front phase difference (R0) of 50 nm and a phase difference (Rth) of 125 nm in a thickness direction is stacked. Cycloolefin polymer (COP).

The upper polarizer and the lower polarizer each form an acrylic adhesive layer between the double-face protective films.

Fig. 3 is a result of applying a voltage to the liquid crystal cell of the liquid crystal display device and calculating a rainbow spot from each direction, and it was confirmed that no rainbow spot was generated at all.

<Example 2>

The first protective film on the upper side and the lower side is uniaxially stretched in the MD direction, and the front surface retardation (R0) of the light source 589 nm is 2000 nm and the refractive index ratio is performed as described in the first embodiment. (NZ) is a polystyrene film (PS) of 0.

Fig. 4 is a graph showing the results of applying a voltage to the liquid crystal cell of the liquid crystal display device and calculating the rainbow spot from each direction, and it was confirmed that no rainbow spot was generated at all.

<Example 3>

Although the implementation is as described in Example 1, the first protective films on the upper side and the lower side are uniaxially stretched in the MD direction, and the front surface retardation (R0) of the light source 589 nm is 1000 nm and the refractive index ratio is stacked. (NZ) is a polyethylene terephthalate (PET).

Fig. 5 is a graph showing the results of applying a voltage to the liquid crystal cell of the liquid crystal display device and calculating the rainbow spot from each direction, and it was confirmed that no rainbow spot was generated at all.

<Example 4>

The first protective film on the upper side and the lower side is uniaxially stretched in the MD direction, and the front surface retardation (R0) of the light source of 589 nm is 500 nm and the refractive index ratio is performed as described in the first embodiment. (NZ) is a polyethylene terephthalate (PET).

Fig. 6 is a graph showing the results of applying a voltage to the liquid crystal cell of the liquid crystal display device and calculating the rainbow spot from each direction, and it was confirmed that the rainbow spot was not generated at all.

<Example 5>

Although implemented as described in Embodiment 1, the first and second protective films of the upper and lower sides of the IPS mode liquid crystal panel are uniaxially stretched in the MD direction, and the front phase difference of the light source of 589 nm is stacked ( R0) is a polyethylene terephthalate (PET) film of 2000 nm and having a refractive index ratio (NZ) of 1.

Fig. 7 is a result of applying a voltage to the liquid crystal cell of the liquid crystal display device and calculating a rainbow spot from each direction, and it was confirmed that no rainbow spot was generated at all.

<Example 6>

Although implemented as described in Example 5, the first and second protective films on the upper side and the lower side are uniaxially stretched in the MD direction, and the front surface retardation (R0) of the light source 589 nm is stacked and 2000 nm and Polystyrene film (polystyrene; PS) having a refractive index ratio (NZ) of 0.

Fig. 8 is a graph showing the results of applying a voltage to the liquid crystal cell of the liquid crystal display device and calculating the rainbow spot from each direction, and it was confirmed that no rainbow spot was generated at all.

<Example 7>

The first protective film on the upper side and the lower side is uniaxially stretched in the MD direction, and the front surface retardation (R0) of the light source of 589 nm is 2000 nm and the refractive index ratio is performed as described in the fifth embodiment. (NZ) is a modified polystyrene film (PS) of 0.

Further, the second protective films on the upper side and the lower side are uniaxially stretched in the MD direction, and stacked with a front side retardation (R0) of a light source of 589 nm and a refractive index ratio (NZ) of 1 polyparaphenylene. Polyethylene terephthalate (PET).

Fig. 9 is a result of applying a voltage to the liquid crystal cell of the liquid crystal display device and calculating a rainbow spot from each direction, and it was confirmed that no rainbow spot was generated at all.

<Example 8>

Although implemented as described in Example 5, the first and second protective films on the upper side and the lower side are uniaxially stretched in the MD direction, and the front surface retardation (R0) of the light source 589 nm is stacked and is 500 nm. A polyethylene terephthalate film (PET) having a refractive index ratio (NZ) of 1.

Fig. 10 is a graph showing the results of applying a voltage to the liquid crystal cell of the liquid crystal display device and calculating the rainbow spot from each direction, and it was confirmed that no rainbow spot was generated at all.

<Example 9>

Although the first and second protective films on the upper side and the lower side are uniaxially stretched in the MD direction, and the front surface retardation (R0) of the light source of 589 nm is 300 nm and A polyethylene terephthalate film (PET) having a refractive index ratio (NZ) of 1.

Fig. 11 is a graph showing the results of applying a voltage to the liquid crystal cell of the liquid crystal display device and calculating the rainbow spot from each direction, and it was confirmed that no rainbow spots were generated at all.

<Example 10>

Although the implementation is as described in Example 5, the first protective films on the upper side and the lower side are uniaxially stretched in the MD direction, and are stacked on the light source at 589 nm with a frontal phase difference (R0) of 300 nm and a refractive index ratio. (NZ) is a modified polystyrene film (PS) of 0.

Fig. 12 is a graph showing the results of applying a voltage to the liquid crystal cell of the liquid crystal display device and calculating the rainbow spot from each direction, and it was confirmed that no rainbow spot was generated at all.

<Example 11>

Although it was carried out as described in Example 5, the first and second protective films on the upper side and the lower side were uniaxially stretched in the MD direction. The first protective film is stacked with a polyethylene terephthalate (PET) having a front surface retardation (R0) of 589 nm and a refractive index ratio (NZ) of 0.8; and a second protection. The film was stacked with a polyethylene terephthalate (PET) having a phase difference (R0) of 300 nm and a refractive index ratio (NZ) of 1.

Fig. 13 is a view showing the result of applying a voltage to the liquid crystal cell of the liquid crystal display device and calculating a rainbow spot from each direction, and it was confirmed that no rainbow spot was generated at all.

<Example 12>

Although it was carried out as described in Example 5, the first and second protective films on the upper side and the lower side were uniaxially stretched in the MD direction. The first protective film is stacked with a modified polystyrene film (polystyrene; PS) having a front phase difference (R0) of 589 nm and a refractive index ratio (NZ) of 0.2; and the second protective film is stacked with a phase. The difference (R0) is a modified polystyrene film (PS) of 300 nm and a refractive index ratio (NZ) of 0.

Fig. 14 is a view showing the result of applying a voltage to the liquid crystal cell of the liquid crystal display device and calculating the rainbow spot from each direction, and it was confirmed that no rainbow spot was generated at all.

<Comparative Example 1>

Although the first protective film of the upper side and the lower side is uniaxially stretched in the TD (transverse direction) direction and stacked with a light source of 589 nm, the front phase difference (R0) is 2000 nm. And the refractive index ratio (NZ) is 1.9.

Fig. 15 is a view showing a result of applying a voltage to a liquid crystal cell of the liquid crystal display device and calculating a rainbow spot from each direction, and confirming that a plurality of rainbow spots are generated.

<Comparative Example 2>

Although implemented as described in Example 1, each of the first protective film on the upper side and the lower side is biaxially stretched, and the front surface retardation (R0) of the light source 589 nm is stacked at 2000 nm and the refractive index ratio (NZ) is stacked. Department 3.

Fig. 16 is a view showing the result of applying a voltage to the liquid crystal cell of the liquid crystal display device and calculating a rainbow spot from each direction, and it was confirmed that a plurality of rainbow spots were generated.

Claims (12)

A polarizing plate is sequentially stacked with a first protective film, a polarizer, a second protective film and an adhesive layer, and the first protective film is uniaxially stretched in the MD direction and front side The phase difference value (R0) is 300 nm or more. The polarizing plate according to claim 1, wherein the first protective film has a front surface retardation value (R0) of 500 nm or more. A polarizing plate is sequentially stacked with a first protective film, a polarizer, a second protective film and an adhesive layer, and the first protective film and the second protective film are uniaxially stretched in the MD direction. Further, the front phase difference value (R0) is 300 nm or more. The polarizing plate according to claim 3, wherein the first protective film and the second protective film each have a front surface retardation value (R0) of 500 nm or more. The polarizing plate of claim 1 or 3, wherein the first protective film has a refractive index ratio (NZ) of 0 ≦ NZ ≦ 1 . The polarizing plate of claim 5, wherein the first protective film has a refractive index ratio (NZ) of 0 or 1. The polarizing plate according to claim 1 or 3, wherein the first protective film is composed of a cycloolefin polymer (COP), a cycloolefin copolymer (COC), and a polyparaphenylene. Polyethylene terephthalate (PET), polypropylene (PP), polycarbonate (PC), polystyrene (PS), polysulfone (PSF) and polymethacrylic acid At least one of the groups consisting of polymethyl methacrylate (PMMA) is selected. The polarizing plate of claim 1 or 3, the first protective film is attached to the polarizer The opposite side of the side includes a surface treatment layer. The polarizing plate of claim 3, wherein the second protective film has a refractive index ratio (NZ) of 0 or 1. The polarizing plate according to claim 3, wherein the second protective film is composed of a cycloolefin polymer (COP), a cycloolefin copolymer (COC), and a polyethylene terephthalate. Polyester terephthalate (PET), polypropylene (PP), polycarbonate (PC), polystyrene (PS), polysulfone (PSF) and polymethyl methacrylate (poly At least one of the groups consisting of methyl methacrylate; PMMA) is selected. A liquid crystal display device comprising the polarizing plate of claim 1 or 3. The liquid crystal display device of claim 11, wherein the backlight is a polarized backlight.