KR101617016B1 - Protective film, polarizer and display device having the same - Google Patents

Abstract

The present invention relates to a protective film, a polarizing plate, and a display device including the same, and is intended to provide a protective film for a polarizing plate having excellent heat resistance and hydrolysis resistance without rainbow stains, and a polarizing plate and a display using the same. It is. In order to achieve the above object, the present invention provides a PVA polarizer characterized by comprising a polyester resin containing a diol component and a dicarboxylic acid component containing 0 mol% or more of 1,4-cyclohexane dimethanol A protective film, a polarizing plate including the protective film, and a display device are provided.

Description

TECHNICAL FIELD [0001] The present invention relates to a protective film, a polarizing plate, and a display device including the polarizing plate,

More particularly, the present invention relates to a protective film having high transmittance, high hydrolysis resistance, and high heat resistance, and a polarizing plate and a display using the protective film.

The polarizing plate has a basic structure of a protective film / PVA / protective film. Among them, TAC (triacetyl cellulose) film is widely used as a protective film for protecting a PVA (polyvinyl alcohol) polarizer. However, since it is vulnerable to moisture, recently, COP (Cyclo Olefin Polymer), acrylic, and polyester films have been applied. As described in Japanese Patent No. 496,666, the protective film can be used as a polarizer protective film by stretching the protective film at least four times in the width direction. However, it is also possible to use a protective film which is excellent in stretch non-uniformity in the width / And there is a problem that the processability is deteriorated due to the crystallization in the width direction. On the other hand, as the thickness becomes thinner in accordance with the demand for thinning, it is necessary to extend the width direction by further stretching in the width direction, but it is necessary to remodel the equipment without changing the resin There is a limit to thinning.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a protective film for a polarizing plate having excellent heat resistance and hydrolysis resistance without rainbow stains, and a polarizing plate and a display using the protective film. have.

According to one aspect of the present invention, there is provided a protective film for a polarizing plate comprising a polyester resin containing a diol component and a dicarboxylic acid component including at least 80 mol% of 1,4-cyclohexanedimethanol.

According to another aspect of the present invention, there is also provided a polarizing element comprising: a polarizer layer; And a protective film adjacent to at least one of an upper surface and a lower surface of the polarizer layer, wherein the protective film contains a diol component and a dicarboxylic acid component including 80 mol% or more of 1,4-cyclohexane dimethanol The present invention provides a polarizing plate comprising a polyester resin.

According to another aspect of the present invention, there is provided a display device comprising: a display panel; And a polarizer disposed on at least one of an upper surface and a lower surface of the display panel, wherein the polarizer comprises a polarizer layer; And a protective film adjacent to at least one of an upper surface and a lower surface of the polarizer layer, wherein the protective film contains a diol component and a dicarboxylic acid component including 80 mol% or more of 1,4-cyclohexane dimethanol The present invention also provides a display device comprising the polyester resin.

The protective film according to the present invention comprises a polyester resin comprising a diol component comprising a high content of 1,4-cyclohexane dimethanol.

Accordingly, the protective film according to the present invention can have high transmittance, high hydrolysis resistance, and high heat resistance.

Also, since the protective film according to the present invention comprises a polyester resin containing a diol component containing a high content of 1,4-cyclohexane dimethanol, even after the stretching process, the retardation in the in-plane retardation and the thickness direction is generally It is smaller than polyester film. That is, in the protective film according to the present invention, the in-plane retardation and the thickness retardation can be expressed similarly after the stretching process. The NZ coefficient that can be expressed by the ratio of the in-plane retardation to the thickness direction retardation satisfies 2 or less, so that rainbow stains can be canceled. With such characteristics, it is possible to overcome the limitations of the processability and thickness for satisfying the characteristics by uniaxial stretching of the polyester system.

As a result, when the protective film according to the present invention is observed from above the side, rainbow stains and the like are not observed, and since it has improved optical characteristics, it can be optimally applied to a polarizing plate.

1 is a cross-sectional view illustrating a polarizing plate according to one embodiment.
2 is a schematic view showing a liquid crystal display device.
3 is a schematic view showing an organic light emitting display device.

In the description of the embodiment according to the present invention, when each film, film, panel or layer is described as being formed "on" or "under" of each film, film, panel, The terms " on "and" under " include all that is formed either directly or indirectly through another element. In addition, the upper and lower standards for each component are described with reference to the drawings. The size of each component in the drawings may be exaggerated for the sake of explanation and does not mean the size actually applied.

1 is a cross-sectional view illustrating a polarizing plate according to one embodiment.

1, a polarizing plate according to an embodiment includes a polarizer layer 220 and a pair of protective films 310 and 320, and has a structure in which a polarizer layer 220 and protective films 310 and 320 are laminated.

The polarizer layer 220 performs a polarization function. The polarizer layer may be a polyvinyl alcohol layer stained with iodine or the like. At this time, the polyvinyl alcohol molecules contained in the polyvinyl alcohol layer may be aligned in one direction.

The protective films 310 and 320 include a polyester resin. That is, the protective films may include a polyester resin. Alternatively, one of the protective films may comprise a polyester resin and the other may comprise an acrylic resin or a triacetyl cellulose resin.

The protective films may be formed entirely of a polyester resin. The polyester resin may be contained in the protective film in an amount of about 90 wt% or more. More specifically, the polyester resin may be contained in the protective film in an amount of about 95 wt% or more. More specifically, the polyester resin may be contained in the protective film in an amount of about 99 wt% or more.

The polyester resin includes a diol component and a dicarboxylic acid component. Here, the polyester resin may consist entirely of a diol component and a dicarboxylic acid component. More specifically, the polyester resin may contain at least about 95 mol% of a diol component and a dicarboxylic acid.

The polyester resin may be formed by polymerizing the diol component and the dicarboxylic acid component after the transesterification reaction.

The diol component comprises 1,4-cyclohexanedimethanol. More specifically, the diol component may comprise at least 80 mol% 1,4-cyclohexane dimethanol. More specifically, the diol component may comprise at least 90 mol% 1,4-cyclohexane dimethanol. More specifically, the diol component may comprise at least 95 mol% 1,4-cyclohexane dimethanol. More specifically, the diol component may comprise at least 99 mol% 1,4-cyclohexane dimethanol.

Specific examples of the diol component that can be used in addition to the 1,4-cyclohexanedimethanol include ethylene glycol, 1,3-propanediol, 1,2-octanediol, 1,3-octanediol, 2,3- , 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol) Propanediol, 2,2-diethyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 3-methyl- , 5-pentanediol, or a mixture thereof.

The dicarboxylic acid component may be an aromatic dicarboxylic acid such as terephthalic acid, dimethylterephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, and orthophthalic acid; Aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid and decanedicarboxylic acid; Alicyclic dicarboxylic acid; And their esterified products can be used alone or in combination of two or more. More specifically, the dicarboxylic acid component may comprise at least about 80 mole% aromatic dicarboxylic acid. More specifically, the dicarboxylic acid component may comprise at least about 80 mole percent terephthalic acid. More specifically, the dicarboxylic acid component may comprise at least about 90 mole percent terephthalic acid. More specifically, the dicarboxylic acid component may comprise at least about 99 mole% terephthalic acid.

The protective film may further include an ultraviolet absorber such as a benzotriazole-based ultraviolet absorber, a penzaphenone-based ultraviolet absorber, or an acrylonitrile-based ultraviolet absorber.

Further, the protective film may be subjected to a corona treatment, a coating treatment, a flame treatment, or the like in order to improve adhesion to the polarizer layer.

In order to improve the adhesion with the polarizer layer, the protective film may be formed on at least one side of the protective film with an adhesive layer mainly composed of at least one of a polyester resin, a polyurethane resin and a polyacrylic resin.

The " main component " refers to a component of 50 mass% or more of the solid components constituting the adhesive layer. The coating liquid used for forming the adhesive layer is preferably an aqueous coating liquid containing at least one of a water-soluble or water-dispersible copolymer polyester resin, an acrylic resin and a polyurethane resin. Examples of the aqueous coating liquid include a water-soluble or water-dispersible copolymer polyester resin solution, an acrylic resin solution, and a polyurethane resin solution.

The thickness of the protective film may be about 10 탆 to about 70 탆. More specifically, the thickness of the protective film may be about 10 탆 to about 60 탆. More specifically, the thickness of the protective film may be from about 10 탆 to about 55 탆.

The transmittance of the protective film may be 80% or more. More specifically, the transmittance of the protective film may be 85% or more. More specifically, the transmittance of the protective film may be 90% or more. More specifically, the transmittance of the protective film may be 95% or more.

The haze of the protective film may be about 10% or less. More specifically, the haze of the protective film may be about 5% or less. More specifically, the haze of the protective film may be about 2% or less.

The in-plane retardation Ro of the protective film may be about 5000 nm or less. More specifically, the in-plane retardation of the protective film may be about 1 nm to about 4000 nm. More specifically, the in-plane retardation of the protective film may be about 1 nm to about 3990 nm.

The thickness direction retardation (Rth) of the protective film may be about 5000 nm or less. More specifically, the retardation in the thickness direction of the protective film may be about 1 nm to about 4000 nm. More specifically, the retardation in the thickness direction of the protective film may be about 1 nm to about 3999 nm.

The protective film may satisfy the following expression (1).

[Equation 1]

0.4? Rth / Ro? 1.8

Here, Rth is the retardation in the thickness direction of the protective film, and Ro is the in-plane retardation of the protective film.

More specifically, Rth / Ro may be 0.4 to 1.6. More specifically, Rth / Ro may be 0.5 to 1.5.

Further, the protective film may be a film that is further stretched in the tenter direction than in the machine direction. More specifically, the protective film may be a film stretched from about 1.01 times to about 1.99 times in the machine direction and from 3.0 times to 10 times in the tenter direction. More specifically, the protective film may be a film stretched from about 1.01 times to about 1.5 times in the machine direction and from about 3.5 times to about 6 times in the tenter direction.

On the contrary, the protective film may be a film which is stretched more in the machine direction than in the tenter direction. More specifically, the protective film may be a film stretched from about 1.01 times to about 1.99 times in the tenter direction and from 3.0 times to 10 times in the machine direction. More specifically, the protective film may be a film stretched from about 1.01 times to about 1.5 times in the tenter direction and about 3.5 times to about 6 times in the machine direction.

Since the protective film contains a polyester resin containing 1,4-cyclohexane dimethanol in a high content, it can have high transmittance, high hydrolysis resistance and high heat resistance.

In addition, since the protective film contains a polyester resin containing a diol component containing a high content of 1,4-cyclohexane dimethanol, the in-plane retardation and the thickness retardation are similar to each other. The NZ coefficient that can be expressed by the ratio of the in-plane retardation to the thickness direction retardation satisfies 2 or less, so that rainbow stains can be canceled. With such characteristics, it is possible to overcome the limitations of the processability and thickness for satisfying the characteristics of the polyester-based uniaxial stretching specified in the above-mentioned technique.

As a result, when the protective film is observed from above the side, rainbow stains and the like are not observed. Thus, the protective film has improved optical properties and can thus be optimally applied for polarizers.

In particular, when the protective film has the in-plane retardation and the thickness direction retardation as described above, it can have the optimum optical properties required for the polarizing plate.

The protective film can be produced by the following process.

First, a polyester resin is prepared. The polyester resin can be formed by the esterification reaction and the polymerization reaction of the diol component and the dicarboxylic acid as described above.

The polyester resin is then melt-extruded and cooled to prepare an unoriented sheet.

Thereafter, the unstretched sheet is stretched in the machine direction and the tenter direction, and is heat set to produce a protective film.

The melt extrusion is preferably performed at a temperature ranging from Tm + 30 占 폚 to Tm + 60 占 폚. If the temperature of the extruder is lower than Tm + 30 ° C in the melt extrusion process, the melt will not be smoothly melted and the viscosity of the extrudate will increase to lower the productivity. On the contrary, if the temperature exceeds Tm + 60 ° C, the molecular weight of the resin decreases due to depolymerization due to thermal decomposition. Problems can arise. Further, the cooling is preferably carried out at a temperature of 30 DEG C or lower, more preferably 15 to 30 DEG C.

The unstretched sheet can be stretched by uniaxial stretching or biaxial stretching.

The unstretched sheet may be stretched at a higher stretch ratio in the second direction than in the first direction. For example, the unstretched sheet may be stretched from about 1.01 times to about 1.99 times in the first direction and from 3.0 times to 10 times in the second direction. More specifically, the unstretched sheet may be stretched from about 1.01 times to about 1.5 times in the first direction and from about 3.5 times to about 6 times in the second direction.

The first direction and the second direction may be perpendicular to each other. The first direction may be a machine direction, and the second direction may be a tenter direction. Conversely, the first direction may be the tenter direction, and the second direction may be the machine direction.

Further, the stretching speed in the machine direction may be about 22 m / min to 500 m / min, preferably 25 m / min to 400 m / min. The stretching speed in the tenter direction may be about 22 m / min to 500 m / min, preferably 25 m / min to 400 m / min.

At this time, if the elongation speed in the machine direction is 22 m / min or more, the desired orientation property can be maintained in the present invention, and crystallinity is imparted depending on the elongation speed in the machine direction and the stretching ratio. It is different.

The stretching temperature is preferably in the range of Tg + 5 deg. C to Tg + 50 deg. C, and the lower the Tg, the better the stretchability, but the breakage may occur. Particularly, in order to improve the brittleness, a stretching temperature range of Tg + 10 deg. C to Tg + 40 deg. C is preferable.

After initiating the heat setting, the film relaxes in the machine direction and / or in the tenter direction, with a heat setting temperature range of 200 [deg.] To 260 [deg.] C being preferred.

Thus, a protective film having an appropriate thickness, in-plane retardation and thickness direction retardation can be produced. Further, the protective film of the present invention may contain various additives such as ordinary electrostatic charge, antistatic, antiblocking agent and other inorganic lubricant within the range that does not impair the effect of this embodiment.

By such a process, the protective film can be produced, and the produced protective film can have improved optical and mechanical properties. In addition, since the protective film formed by the above process has low heat shrinkage, the polarizer layer can be efficiently protected.

Accordingly, the polarizing plate according to this embodiment can have improved optical characteristics, mechanical properties, and thermal properties.

Display device

The polarizing plate according to this embodiment can be applied to a display device such as a liquid crystal display device or an organic light emitting display device.

Liquid crystal display ( liquid crystal display ; LCD )

2 is a cross-sectional view schematically showing a liquid crystal display device according to the present embodiment. Referring to FIG. 2, the liquid crystal display according to the present embodiment includes a liquid crystal panel and a backlight unit 20.

The backlight unit 20 emits light to the liquid crystal panel. The liquid crystal panel displays an image using light from the backlight unit 20. [ More specifically, the liquid crystal panel displays an image by adjusting the intensity of light emitted in units of pixels using light from the backlight unit 20. [

The liquid crystal panel includes an upper polarizer 11, a color filter substrate 13, a liquid crystal layer 14, a TFT substrate 15, and a lower polarizer 12, which are stacked.

The TFT substrate 15 and the color filter substrate 13 are opposed to each other. The TFT substrate 15 includes a plurality of pixel electrodes corresponding to each pixel, thin film transistors connected to the pixel electrodes, a plurality of gate wirings for applying driving signals to the thin film transistors, And may include a plurality of data lines for applying data signals to the pixel electrodes through the thin film transistors.

The color filter substrate 13 includes a plurality of color filters corresponding to respective pixels. The color filters may filter the transmitted light to realize red, green, and blue, respectively. The color filter substrate 13 may include a common electrode facing the pixel electrodes.

The liquid crystal layer 14 is interposed between the TFT substrate 15 and the color filter substrate 13 and can be driven by the TFT substrate 15. More specifically, the liquid crystal layer 14 may be driven by an electric field formed between the pixel electrodes and the common electrode. The liquid crystal layer 14 can control the polarization direction of light passing through the lower polarizer 12. That is, the TFT substrate 15 can control the potential difference applied between the pixel electrodes and the common electrode in pixel units. Accordingly, the liquid crystal layer 14 can be driven to have different optical characteristics in pixel units.

At least one of the upper polarizer 11 and the lower polarizer 12 may have substantially the same configuration as the polarizer of the above-described manufacturing method.

The lower polarizer plate 12 is disposed below the TFT substrate 15. The lower polarizer plate 12 may be adhered to the lower surface of the TFT substrate 15.

The upper polarizer 11 is disposed on the color filter substrate 13. The upper polarizer 11 may be adhered to the upper surface of the color filter substrate 13.

The polarization directions of the upper polarizer 11 and the lower polarizer 12 may be the same or perpendicular to each other.

As described above, the upper polarizer 11 and / or the lower polarizer 12 include a protective film having an improved performance. Accordingly, the liquid crystal display device according to the present embodiment can have improved brightness, image quality, and durability.

Organic electroluminescence  Display device ( organic 선택 display )

3 is a cross-sectional view illustrating an organic light emitting display device according to an exemplary embodiment of the present invention.

Referring to FIG. 3, the organic light emitting display according to the present embodiment includes a front polarizer 16 and an organic electroluminescent panel.

The front polarizer 16 may be disposed on the front surface of the organic electroluminescent panel. More specifically, the front polarizer 16 may be adhered to a surface of the organic electroluminescent panel on which an image is displayed. The front polarizer plate 16 may have substantially the same configuration as the polarizer plate in the above-described manufacturing method.

The organic electroluminescent panel displays an image by self-emission of a pixel unit, and includes an organic electroluminescent substrate 31 and a driving substrate 32.

The organic electroluminescent substrate 31 includes a plurality of organic electroluminescent units corresponding to pixels. Each of the organic electroluminescent units includes a cathode, an electron transport layer, a light emitting layer, a hole transport layer, and a cathode.

The negative electrode and the positive electrode are opposed to each other. Further, the negative electrode and the positive electrode are disposed to be spaced apart from each other. At least one of the cathode and the anode is transparent. More specifically, at least one of the cathode and the anode may comprise a transparent conductive oxide.

The light emitting layer, the electron transporting layer, and the hole transporting layer are interposed between the cathode and the anode. The electron transporting layer is adjacent to the cathode, and the hole transporting layer is adjacent to the anode. The light emitting layer is interposed between the electron transporting layer and the hole transporting layer. That is, the organic electroluminescent units may be arranged in the order of a cathode, an electron transporting layer, a light emitting layer, a hole transporting layer, and a cathode.

The anode may be transparent. Examples of the material used as the anode include indium tin oxide (ITO) and the like. In addition, the cathode may include a metal having a low work function such as aluminum. Light is emitted through the anode, and an image can be displayed.

The electron transporting layer transports electrons from the cathode to the light emitting layer. Examples of the material used for the electron transporting layer include tris (8-hydroxyquinolinato) aluminum (Alq3) and tris (8-hydroxyquinolinato) aluminum.

The hole transporting layer transports holes from the anode to the light emitting layer. Examples of the material used as the hole transporting layer include N, N'-diphenyl-N, N'-bis (1-naphthyl) -1,1'-biphenyl-4,4'- N'-diphenyl-N, N'-bis (1-naphthyl) -1,1'-biphenyl-4,4'-diamine); NPB).

The light-emitting layer combines electrons from the electron transport layer and holes from the hole transport layer to generate light. The light emitting layer may include a host and a dopant doped to the host. Examples of the material used as the host include carbazole-based or anthracene-based organic materials. Examples of the material used as the dopant include blue, green or red fluorescent materials.

The driving substrate 32 is drivingly coupled to the organic electroluminescence substrate 31. That is, the driving substrate may be coupled to the organic electroluminescence substrate 31 to apply a driving signal such as a driving current. More specifically, the driving substrate 32 can drive the organic electroluminescent substrate 31 by applying a current to the organic electroluminescent units.

The driving substrate 32 may include a plurality of gate lines, a plurality of data lines, and a plurality of thin film transistors.

Since the front polarizer 16 has improved optical characteristics, mechanical characteristics, and thermal characteristics, the organic light emitting display device according to the present embodiment can have improved brightness, image quality, and durability.

Hereinafter, the present invention will be described in more detail by way of examples. The following examples are illustrative of the present invention, but the present invention is not limited to the following examples.

Manufacturing example

When the temperature of the esterification reaction tube was elevated to 200 占 폚, 86.4 parts by mass of terephthalic acid and 64.6 parts by mass of 1,4-cyclohexanedimethanol were added and 0.017 part by mass of manganese acetate was added as a catalyst while stirring. Subsequently, pressure elevation was carried out, and the esterification reaction was carried out under the conditions of gauge pressure 0.34 MPa and 240 deg. C, and then the esterification reaction tube was returned to normal pressure and 0.014 mass part of phosphoric acid was added. Further, the temperature was raised to 260 DEG C over 15 minutes, and 0.012 parts by mass of trimethyl phosphate was added. After 15 minutes, dispersion treatment was carried out with a high-pressure disperser. After 15 minutes, the obtained esterification reaction product was transferred to a polycondensation reaction tube and subjected to a polycondensation reaction under reduced pressure at 280 占 폚.

After completion of the polycondensation reaction, the mixture was filtered with a nylon filter having a cut-off size of 95% of 5 mu m, extruded from a nozzle into a strand shape, and cooled using cooling water previously subjected to filtration treatment (pore size: And solidified and cut into pellets.

The viscosity of the obtained poly (1,4-cyclohexanedimethanol terephthalate) resin was 0.62.

Example

The poly (1,4-cyclohexanedimethanol terephthalate) resin thus produced was melt-extruded through an extruder at about 290 ° C, and then cooled on a casting roll at about 20 ° C to prepare an unoriented sheet. The unstretched sheet thus obtained was immediately heated to 80 ° C and then stretched at about 110 ° C in the machine direction and the tenter direction at the stretching ratio shown in Table 1 below. Thereafter, the stretched sheet was heat set at a temperature of about 222 캜 for about 30 seconds.

Comparative Example

A polyethylene terephthalate resin (SKC product) was used instead of the poly (1,4-cyclohexanedimethanol terephthalate) resin. The PET resin was extruded through an extruder at a temperature of about 285 DEG C, To produce an unoriented sheet. Such an unstretched sheet was stretched in the machine direction and the tenter direction at a stretching ratio shown in Table 1 below at a temperature of 125 캜 after the preheating. Thereafter, the stretched sheet was heat set at a temperature of about 225 DEG C for about 30 seconds.

The thus prepared protective films were evaluated as follows.

(1) In-plane retardation (Ro)

The in-plane retardation is a parameter defined by a product (DELTA Nxy x d) of the anisotropy (DELTA Nxy = | Nx-Ny |) of the refractive index of the orthogonal biaxial film on the film and the film thickness d (nm), and represents optical anisotropy and anisotropy It is a scale. The in-plane retardation (Ro) of the film was measured at a wavelength of 550 nm using a polarization / phase contrast film measuring apparatus (Model: RETS-100) manufactured by Ostuka. On the other hand, the phase difference can be calculated by the following series of processes. The anisotropy (? Nxy) of the refractive index of the biaxial axis was obtained by the following method. Two polarizing plates were used to determine the orientation axis direction of the film, and a rectangle of 4 cm x 2 cm was cut out so that the orientation axis direction was orthogonal to each other. The refractive index (Nx, Ny) and the refractive index (Nz) in the thickness direction orthogonal to the sample were determined by Abbe's refractive index meter (NAR-4T manufactured by Atago Corporation, measurement wavelength: 589 nm) The value (| Nx-Ny |) is defined as anisotropy (? Nxy) of the refractive index. The thickness d (nm) of the film was measured using an electric micrometer (Millitron 1245D, manufactured by Pahrung Paste), and the unit was converted to nm. The retardation Re can be obtained from the product (Nxy x d) of the anisotropy (DELTA Nxy) of the refractive index and the thickness d (nm) of the film.

(2) Thickness direction retardation (Rth)

The retardation in the thickness direction means the retardation obtained by multiplying the birefringence ΔNxz (= | Nx-Nz |) and ΔNyz (= | Ny-Nz | . The in-plane retardation (Rth) of the film was measured at a wavelength of 550 nm using a polarizing / phase contrast film measuring apparatus (model name: RETS-100) manufactured by Ostuka. On the other hand, the phase difference can be calculated by the following series of processes. Nx, Ny, and Nz and the film thickness d (nm) were obtained in the same manner as in the measurement of the retardation, and the average value of (DELTA Nxz x d) and (DELTA Nyz x d) was calculated to calculate the thickness direction retardation (Rth) Respectively.

(3) Rainbow color stain observation

A polyester film produced by a method described later on one side of a polarizer made of PVA and iodine was stuck to the polarizer so that the absorption axis of the polarizer and the main axis of alignment of the film were perpendicular to each other, and a TAC film (manufactured by Fuji Film Co., Thickness: 80 占 퐉) was attached thereto to prepare a polarizing plate. The obtained polarizing plate was set so that the polyester film was on the viewer's side of a light emitting side of a liquid crystal display device using a white LED as a light emitting element (Nichia Chemical, NSPW500CS) in which a blue light emitting diode and a yttrium aluminum garnet yellow phosphor were combined Respectively. This liquid crystal display device has a polarizing plate that uses two TAC films as a polarizer protective film on the incident light side of the liquid crystal cell. The presence or absence of rainbow color unevenness was visually observed from the front and the oblique direction of the polarizing plate of the liquid crystal display device as follows,

◎: Rainbow color unevenness does not occur in any direction.

○: When observed in the oblique direction, some very light rainbow irregularities were observed.

X: Rainbow color unevenness was clearly observed when observed in the oblique direction.

As can be seen from the results in Table 2, it is possible to apply thinner protective films without rainbow stains by using PCT. However, it can be seen that the thickness of PET is limited.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the scope of the present invention is not limited to the disclosed exemplary embodiments. Forms are also included within the scope of the present invention.

11: Upper polarizer 12: Lower polarizer
13: color filter substrate 14: liquid crystal layer
15: TFT substrate 16: front polarizer
20: backlight unit 31: organic electroluminescence substrate
32: driving substrate 220: polarizer layer
310, 320: protective film

Claims (12)

Cyclohexane dimethanol, and a dicarboxylic acid component, wherein the component further used in the diol component is at least one selected from the group consisting of ethylene glycol, 1,3-propane Diol, 1,2-octanediol, 1,3-octanediol, 2,3-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 2,2- Propane diol (neopentyl glycol), 2-butyl-2-ethyl-1,3-propanediol, 2,2-diethyl- Diol, 3-methyl-1,5-pentanediol, and 1,1-dimethyl-1,5-pentanediol, or a mixture of two or more thereof, To 1.99 times in the tenter direction, 3.0 to 10 times in the tenter direction, 1.01 to 1.99 times in the tenter direction, 3.0 to 10 times in the machine direction, and satisfies the following formula PV A Protective film for polarizer.
[Equation 1]
0.4? Rth / Ro? 1.8
(Where Rth is the retardation in the thickness direction of the protective film for the polarizer at a wavelength of 550 nm and Ro is the in-plane phase difference of the protective film for the polarizer at the wavelength of 550 nm)
The process of claim 1, wherein the dicarboxylic acid component comprises an aromatic dicarboxylic acid and the diol component comprises less than 100 mole% 1,4-cyclohexanedimethanol. Protective film for PVA polarizer.
The protective film for a PVA polarizer according to claim 1, wherein the in-plane retardation at a wavelength of 550 nm is 1 nm to 4000 nm.
The protective film for a PVA polarizer according to claim 3, wherein the retardation in the thickness direction at a wavelength of 550 nm is 1 nm to 4000 nm.
The protective film for a PVA polarizer according to claim 4, which has a thickness of 10 탆 to 60 탆.
delete delete A polarizer layer; And
And a protective film adjacent to at least one of the upper surface and the lower surface of the polarizer layer,
Wherein the protective film is any one of the protective films for polarizers selected from those of claims 1 to 5
. ≪ / RTI >
9. The polarizer of claim 8, wherein the dicarboxylic acid component comprises benzene dicarboxylic acid or naphthalene dicarboxylic acid.
delete delete Display panel; And
And a polarizing plate disposed on at least one of an upper surface and a lower surface of the display panel,
The polarizing plate
A polarizer layer; And
And a protective film adjacent to at least one of the upper surface and the lower surface of the polarizer layer,
Wherein the protective film is a protective film for any one of the polarizers selected from among the above-mentioned first to fifth aspects.

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