KR101768253B1 - Polarizing plate, method for preparing the same and liquid crystal display apparatus comprising the same - Google Patents

Abstract

The present invention provides a polarizer comprising: a polarizer; And an in-plane retardation (Re) of 500 nm or less as expressed by the formula (1) at a wavelength of 550 nm, and a thickness represented by the formula (2), wherein the stretching ratio in the MD direction: TD is in the range of 1: 0.8 to 1: A polarizing plate including a polyester film having a directional phase difference (Rth) of 10,000 nm or less, a method for producing the same, and a liquid crystal display device including the same.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarizing plate, a method of manufacturing the same, and a liquid crystal display device including the polarizing plate,

The present invention relates to a polarizing plate, a manufacturing method thereof, and a liquid crystal display device including the same.

The polarizing plate is used in and out of the liquid crystal cell for the purpose of controlling the direction of light oscillation in order to visualize the display pattern of the liquid crystal display device. Liquid crystal display devices have been used in a wide range from small-sized devices at the beginning of development to notebook computers, liquid crystal monitors, liquid crystal color projectors, liquid crystal televisions, navigation systems for vehicles, personal phones, and measurement devices used indoors and outdoors Respectively. Particularly, liquid crystal monitors, liquid crystal televisions, and the like are often used in high luminance backlights among applications of liquid crystal display devices. Therefore, the polarizing film used for the polarizing plate is required to have higher performance than that of the conventional product.

The polarizing plate includes a polarizer, a protective film formed on one surface of the polarizer and protecting the polarizer, and typically triacetylcellulose (TAC) film is used, but the TAC film is more expensive than a general polymer film.

In order to replace the TAC film, a low-cost polymer film including a polyethylene terephthalate (PET) film is used. In order to increase the yield, the PET film is stretched at a high magnification so that the retardation is large. Rainbow stains may occur and image quality may be deteriorated.

In this regard, Korean Patent Publication No. 2008-0099588 discloses a polarizing plate comprising a polyethylene terephthalate film on one side of a polarizer and having a haze of 15% or more and 45% or less.

An object of the present invention is to provide a polarizing plate comprising a stretched polyester film and preventing rainbow stains from occurring on the front surface as well as the side surface when mounted on a liquid crystal display panel.

One aspect of the present invention is a polarizer comprising a polarizer; And an in-plane retardation (Re) expressed by the following formula (1) at a wavelength of 550 nm of not more than 500 nm, and a refractive index And a polyester film having a thickness direction retardation (Rth) of 10,000 nm or less.

<Formula 1>

Re = (nx - ny) xd

<Formula 2>

Rth = ((nx + ny) / 2 - nz) xd

(Wherein nx, ny, nz, d are as defined below).

The stretching ratio of the polyester film in the MD direction may be 1: 1 in the TD direction.

 The polyester film may have a degree of biaxiality (NZ) represented by the following formula 3: 15 to?

<Formula 3>

NZ = (nx - nz) / (nx - ny)

(Wherein nx, ny and nz are as defined below).

The polyester film may be non-birefringent.

The polyester film may be a film made of one or more resins selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate and polybutylene naphthalate.

And an optical film on the lower surface of the polarizer.

The optical film may be a retardation film.

In the optical film, the optical film may be at least one selected from the group consisting of cellulose, polyester, cyclic polyolefin, polycarbonate, polyether sulfone, polysulfone, polyamide, polyimide, polyolefin, polyarylate, Alcohol-based, polyvinyl chloride-based, and polyvinylidene chloride-based resins.

Another method of producing a polarizing plate according to another aspect of the present invention is a method of producing a polyester film by simultaneously stretching the melt-extruded polyester resin in the MD direction and the TD direction so that the stretching ratio in the MD direction: TD direction is 1: 0.8 to 1: 1.2 , And adhering the polyester film to the upper surface of the polarizer.

The polyester resin may include at least one of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate.

The stretching ratio in the MD direction: the stretching ratio in the TD direction may be 1: 1.

And further adhering an optical film to the lower surface of the polarizer.

The liquid crystal display device according to another aspect of the present invention may include the polarizing plate.

According to the present invention, there is provided a polarizing plate comprising a stretched polyethylene terephthalate film as a protective film, wherein iridescence is not generated on the front surface as well as on the side surface when the film is attached to a liquid crystal display panel.

1 is a cross-sectional view of a polarizing plate of one embodiment of the present invention.
2 is a cross-sectional view of a module for a liquid crystal display device according to one embodiment of the present invention.

The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

In the present specification, 'upper' and 'lower' are defined with reference to drawings, and 'upper' may be changed to 'lower' and 'lower' may be changed to 'upper' depending on viewing time.

Herein, 'side' may be a viewing angle of up / down / left / right of 0 ° to less than 90 °, more than 90 ° and 180 °.

In this specification, the term "stretching ratio" means the ratio of the length after stretching to the length of the initial polyester film when stretched in the longitudinal direction and the width after stretching to the width of the original polyester film when stretched in the width direction.

1 is a cross-sectional view of a polarizing plate of one embodiment of the present invention.

1, the polarizing plate 100 includes a polarizer 110, a polyester film 120 formed on the upper surface of the polarizer 110, and an optical film 130 formed on the lower surface of the polarizer 110 .

The polyester film is a biaxially stretched film, which is a film stretched simultaneously in the MD (machine direction) direction and the TD (transverse direction) direction. The MD film stretching ratio in the TD stretching ratio is 1: 0.8 to 1: 1.2, preferably 1: . If the value of the stretching ratio in the TD direction with respect to the MD direction stretching ratio is less than 0.8 and more than 1.2, the in-plane retardation (Re) of the polyester film may be high, and iridescence may occur.

In embodiments, the MD direction stretch ratio: TD stretch ratio is 1: 0.85 to 1: 1.15, or 1: 0.9 to 1: 1.1, or 1: 0.95 to 1: 1.05, or 1: 0.96 to 1: 1: 0.98 to 1: 1.09 or 1: 0.98 to 1: 1.08 or 1: 0.99 to 1: 1.01 or 1: : 1.07.

In one embodiment, the MD direction stretching ratio may be 1.0 to 4.0, for example, 2.5 to 3.5, and the TD stretching ratio may be 1.0 to 4.0, for example, 2.5 to 3.5. In the above range, since the stretching ratio in the MD direction and the stretching ratio in the TD direction are substantially the same, it is possible to prevent the occurrence of rainbow stains on the front surface and the side surface when used in a polarizing plate.

The polyester film has a low retardation by simultaneously stretching the film in the MD direction and the TD direction at substantially the same stretching ratio, thereby preventing occurrence of rainbow stains on the front side and the side surface. In one embodiment, the polyester film may have an in-plane retardation (Re) of 500 nm or less and a thickness direction retardation (Rth) represented by the following formula 2 at a wavelength of 550 nm,

<Formula 1>

Re = (nx - ny) xd

<Formula 2>

Rth = ((nx + ny) / 2 - nz) xd

(Where nx, ny and nz are the refractive indices of the film in the x-, y- and z-axis directions, respectively, and d is the thickness (unit: nm) of the film).

When Re and Rth are in the above ranges, iridescent spots do not occur on the front and side surfaces when applied to a polarizing plate, and optical quality is excellent when the liquid crystal display panel is mounted on the liquid crystal display panel. Preferably, Re is 0 to 500 nm or less, more preferably 0 to 400 nm, still more preferably 0 to 200 nm, even more preferably 0 nm. Rth may be from 0 to 10,000 nm, preferably from 0 to 4,000 nm, or preferably from 3,000 to 10,000 nm.

Polyester film to the one or more biaxial degree (NZ) of the formula 3, more preferably from 15 to ∞ (e.g. 15 to 10 ^{10 000),} more preferably from 50 to ∞ (e.g. 50 to 10 ^{10 000} ), Which may be infinite, for example:

<Formula 3>

NZ = (nx - nz) / (nx - ny)

(Where nx, ny, and nz are the refractive indices of the polyester film in the x-, y-, and z-axis directions, respectively).

Within this range, there may be the best image quality and rainbow spot smearing effect. In the polyester film, the x-axis direction indicates the MD direction, the y-axis direction indicates the TD direction, and the z-axis direction indicates the thickness direction.

The polyester film has nx-ny at a wavelength of 550 nm, and nx-ny is 0 to 0.1, preferably 0 to 0.01. The closer to 0, the better the NZ can be. In the above range, when used as a protective film, it is possible to prevent occurrence of rainbow stains on the front surface and the side surface, and it is possible to have an effect that rainbow stains are not caused by a small change in the retardation value depending on the incident angle and wavelength.

The polyester film becomes non-birefringent without birefringence, and when a protective film is used, it is possible to prevent the occurrence of rainbow stains on the front surface and the side surface, and the retardation value changes little depending on the incident angle and wavelength, .

The polyester film is not particularly limited as long as it is a transparent resin as the polyester resin. In an embodiment, the polyester film may be a film of one or more resins selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate.

The polyester film may have a thickness of 25 占 퐉 to 500 占 퐉. In the above range, it can be used as a polarizing plate upon lamination to a polarizer. For example, 25 占 퐉 to 200 占 퐉, for example, 25 占 퐉 to 115 占 퐉.

The polyester film may have a haze of less than 2%, for example less than 1%, for example 0.1 to 1.9% or 0.1 to 0.9%. The polyester film of the present invention has a low retardation even when the haze is less than 2%, thereby preventing rainbow stains.

The polyester film may include a functional coating layer on its upper surface, for example, a hard coating layer, an antireflection layer or an inner fingerprint layer to impart functionality. The functional coating layer may have a thickness of 25 mu m to 100 mu m. In the above range, it can be used as a polarizing plate upon lamination to a polarizer.

The polyester film may further include a surface coating layer on the lower surface. The surface of the polyester film is hydrophobic, and the hydrophobicity is particularly large when the polyethylene terephthalate film is used as a protective film. In order to use such a film as a polarizing plate, a surface modification that converts it to a hydrophilic property is required. The surface modification of the conventional cellulose-based film may not sufficiently modify the surface of the film or may damage the surface of the film using the sodium hydroxide-based surface modification method. To this end, a surface coating layer comprising a primer having hydrophobic and hydrophilic functional groups can be formed on the protective film. The primer having a hydrophobic and hydrophilic functional group may include, but is not limited to, a polyester-based resin, a polyvinyl acetate-based resin, or a combination thereof. By adding the surface coating layer, the mechanical properties of the protective film and the low moisture permeability are maximized, so that a high resistance to external harsh conditions can be added to the polarizing plate. Further, the surface coating layer is formed between the protective film and the polarizing plate, so that the adhesion between the protective film and the polarizing film can be improved.

The polarizer is molecularly oriented in a specific direction. When the polarizer is attached to a liquid crystal display device, it transmits only light in a specific direction. The polarizer can be produced by dyeing a polyvinyl alcohol film with iodine or a dichroic dye and stretching it in a certain direction. Specifically, it is produced through a swelling process, a dyeing step, a stretching step and a crosslinking step. Methods of performing each step are commonly known to those skilled in the art.

The polarizer may have a thickness of 10 탆 to 30 탆. In the above range, it can be used for a polarizing plate for a liquid crystal display.

The optical film may be formed on the liquid crystal display panel by a pressure-sensitive adhesive and have a viewing angle compensation function by having a retardation in a predetermined range. In an embodiment, the optical film may have a front retardation (Ro) of 30 to 60 nm at a wavelength of 550 nm. When the light passes through the liquid crystal cell in the above range, it may compensate the birefringence caused by the liquid crystal cell and enlarge the viewing angle to enlarge the viewing angle and compensate the black and white.

The optical film is a transparent optical film, which is a non-polyester film other than a polyester film or a polyester film, such as cellulose-based film including triacetyl cellulose or the like, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, Polyamide-based, polyimide-based, polyolefin-based, polyarylate-based, polyvinyl alcohol-based, polychlorinated-polyolefin-based, polycarbonate-based, polyether sulfone-based, Vinyl-based resin, polyvinylidene chloride-based resin, vinyl-based resin, and polyvinylidene chloride-based resin.

The optical film may have a thickness of 10 탆 to 500 탆. In the above range, it can be used for a polarizing plate for a liquid crystal display.

An adhesive layer is formed between the polarizer and the polyester film and between the polarizer and the optical film to increase the mechanical strength of the polarizing plate. The adhesive layer may include at least one of ordinary adhesives such as an aqueous adhesive, a pressure-sensitive adhesive, and a photocurable adhesive.

The thickness of the polarizing plate may be 25 占 퐉 to 500 占 퐉. In the above range, it can be used for a polarizing plate for a liquid crystal display. The polarizing plate may have a degree of polarization of 99% or more, for example, 99.9 to 99.999%, and a transmittance of 40% or more, for example, 40 to 80%. In the above-mentioned range, there may be no deterioration of the optical characteristics when the liquid crystal display device is mounted.

Another method of producing a polarizing plate according to another aspect of the present invention is a method of producing a polyester film by simultaneously stretching the melt-extruded polyester resin in the MD direction and the TD direction so that the stretching ratio in the MD direction: TD direction is 1: 0.8 to 1: 1.2 , And bonding the polyester film to the polarizer.

The stretching ratio in the MD direction: the stretching ratio in the TD direction is 1: 0.8 to 1: 1.2. However, the polarizing plate comprising the polyester film produced by sequentially stretching in the MD direction from the MD direction or sequentially from the TD direction to the MD direction has a refractive index and a retardation control There is a problem of rainbow stains. Even if stretched in the MD direction and the TD direction at the same time, the polarizing plate including the polyester film produced in the MD direction stretching ratio: TD stretching ratio out of the above range may have a problem of image quality deterioration and rainbow stain have. The stretching ratio in the MD direction may be 1 to 4, and the stretching ratio in the TD direction may be 1 to 4.

By simultaneous stretching in the MD and TD directions, the refractive index and the retardation of the polyester film can be easily controlled and iridescence unevenness may not occur.

The stretching can be performed by at least one of dry stretching and wet stretching, and the stretching temperature can be stretched at (Tg - 20) ° C to (Tg + 50) ° C based on the Tg of the polyester resin. For example, the stretching temperature is usually 70 to 150 占 폚, preferably 80 to 130 占 폚, and more preferably 90 to 120 占 폚. The number of stretching is not particularly limited, and if stretching ratio is obtained, stretching may be performed a plurality of times.

Polarizers can be prepared by dyeing a polyvinyl alcohol film with iodine or a dichroic dye and stretching it in a certain direction. Methods of performing each step are generally known to those skilled in the art.

The polyester film can be adhered to a polarizer by a usual method, and the adhesive may include at least one of an aqueous adhesive, a pressure-sensitive adhesive, and a photo-curable adhesive.

The manufacturing method may further include a step of adhering the optical film to the polarizer with an adhesive, and the adhesive may include at least one of an aqueous adhesive, a pressure sensitive adhesive, and a photocurable adhesive.

A liquid crystal display device according to another aspect of the present invention may include a module for a liquid crystal display device including the polarizing plate.

2 is a cross-sectional view of a module for a liquid crystal display device according to one embodiment of the present invention.

2, a liquid crystal display module 200 includes a liquid crystal display panel 205, a first polarizer 220 formed on the upper surface of the liquid crystal display panel 205, a lower surface of the liquid crystal display panel 205, And a second polarizing plate 230 formed between the liquid crystal display panel 205 and the light source 240. The first polarizing plate 220 includes a first optical film 222 formed on the upper surface of the liquid crystal display panel 205, A first polarizer 224 formed on the upper surface of the first optical film 222 and a first polyester film 226 formed on the upper surface of the first polarizer 224, The second polarizer 234 formed on the lower surface of the second optical film 232 and the second polarizer 234 formed on the lower surface of the second polarizer 234 formed on the lower surface of the display panel 205, And a polyester film 236.

The liquid crystal display panel 205 includes a liquid crystal panel including a liquid crystal cell layer 212 sealed between a first substrate 210a and a second substrate 210b. The first polarizing plate and the second polarizing plate may be laminated, respectively. In one embodiment, the first substrate may be a color filter (CF) substrate (upper substrate), and the second substrate may be a TFT (thin film transistor) substrate (lower substrate).

The first substrate and the second substrate may be the same or different, and may be a glass substrate or a plastic substrate. The plastic substrate is made of polyethylene terephthalate (PET), polycarbonate (PC), polyimide (PI), polyethylene naphthalate (PEN), polyether sulfone (PES), polyarylate (PAR) and cycloolefin copolymer (COC) Or the like, but the present invention is not limited thereto.

The liquid crystal cell layer may be a liquid crystal cell layer including a VA (Vertical Alignment) mode liquid crystal, an IPS (In Place Switching) mode, a FFS (Fringe Field Switching) mode and a TN (Twisted Nematic) mode liquid crystal.

Hereinafter, the configuration and operation of the present invention will be described in more detail with reference to preferred embodiments of the present invention. It is to be understood, however, that the same is by way of illustration and example only and is not to be construed in a limiting sense.

Specific specifications of the components used in the following examples and comparative examples are as follows.

(1) Polarizer material: polyvinyl alcohol film (VF-PS6000, Kuraray Co., Ltd., thickness: 60 m)

(2) Polyester film: polyethylene terephthalate film (COSMOSHINE TA015, TOYOBO, thickness: 100 탆, haze: less than 1%)

(3) Optical film: A triacetylcellulose film (KC4DR-1, Fuji, Japan, thickness: 40 탆) was used.

Example  1 to 4

Polarizers were prepared by subjecting the material of the polarizer to a process such as dyeing and drawing. Specifically, the polyvinyl alcohol film was stretched three times at 60 ° C, adsorbed iodine, and then stretched 2.5 times in an aqueous boric acid solution at 40 ° C to prepare a polarizer. The polyethylene terephthalate film was dry-stretched at 100 DEG C by simultaneous stretching under the conditions shown in Table 1 below, laminated on the upper surface of the polarizer using an adhesive, and the optical film was laminated on the lower surface of the polarizer using an adhesive, .

Comparative Example  1 to 4

A polarizing plate was produced in the same manner as in Example 1 except that the stretching conditions of the polyethylene terephthalate film were changed as shown in Table 1 below.

The following properties of the polarizing plates prepared in the above Examples and Comparative Examples were evaluated, and the results are shown in Table 1 below.

division Stretching condition Re (nm) Rth (nm) NZ Rainbow spot occurrence Drawing sequence MD stretching ratio TD stretching ratio face side Example 1 Simultaneous stretching in MD direction and TD direction 3.1 3.3 500 9800 20.1 × × Example 2 Simultaneous stretching in MD direction and TD direction 3.1 3.2 200 6800 34.5 × × Example 3 Simultaneous stretching in MD direction and TD direction 2.9 2.9 0 4200 ∞ × × Example 4 Simultaneous stretching in MD direction and TD direction 2.6 2.6 0 1000 ∞ × × Comparative Example 1 Stretching in the MD direction followed by stretching in the TD direction 2.5 2.5 1320 13200 10.5 ◎ ◎ Comparative Example 2 After stretching in the TD direction, stretching in the MD direction 2.7 2.8 1900 15800 8.8 ◎ ◎ Comparative Example 3 Simultaneous stretching in MD direction and TD direction 2.5 3.4 4250 14500 3.9 ○ ◎ Comparative Example 4 Simultaneous stretching in MD direction and TD direction 1.8 3.5 5400 16500 3.6 △ ○

(1) Phase difference value: The in-plane retardation (Re) and the thickness direction retardation (Rth) at a wavelength of 550 nm of the polyethylene terephthalate film were measured using Axo Scan of Axo Metrix Co.,

(2) Whether rainbow stains occur: Assemble the polarizing plate on the liquid crystal display panel including the VA mode liquid crystal. A polarizing plate was assembled such that optical films were in contact with the upper and lower surfaces of the liquid crystal display panel, respectively. (Irregularities in the direction of viewing angle of 90 degrees) and sides (viewing angle of 45 degrees or 135 degrees) were observed using a spectral radiance spectrometer (SR-3A, Topcon). A case where iridescence is not generated, a case where iridescence occurs weakly, a case where iridescence occurs moderately, a case where iridescence occurs strongly, and a case where iridescence occurs strongly.

As shown in Table 1, the polarizing plate of the present invention not only had no rainbow stains on the front but also had iridescent stains on its side. On the other hand, Comparative Examples 1 and 2, which were not elongated in the MD direction and the TD direction at the same time, had a problem of rainbow stains due to the unevenness in the draw ratio unevenness even when the MD direction: TD direction stretching ratio satisfied the stretching ratio range of the present invention. Comparative Examples 3 to 4, which were out of the stretching ratio range of the present invention even when stretched, had a problem of rainbow staining due to the effect of birefringence.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (16)

A polarizer; And
And a retardation film formed on the light exit surface of the polarizer and being biaxially stretched in the MD and TD directions simultaneously and having an MD stretch ratio in the TD stretch ratio of 1: 0.8 to 1: 1.2 and a wavelength of 550 nm, A retardation film (Re) of 0 nm to 500 nm, and a thickness direction retardation (Rth) represented by the following formula (2): 1,000 nm to 10,000 nm,
<Formula 1>
Re = (nx - ny) xd
(Where nx and ny are refractive indices of the polyester film in the x- and y-axis directions, respectively, and d is the thickness (unit: nm) of the polyester film)
<Formula 2>
Rth = ((nx + ny) / 2 - nz) xd
(Where nx, ny and nz are the refractive indices of the polyester film in the x-, y- and z-axis directions and d is the thickness (unit: nm) of the polyester film)
When the refractive index of the polyester film is 550 nm, the refractive index in the x-axis direction is nx, and the refractive index in the y-axis direction is ny, nx-ny is 0 to 0.1,
Wherein the polyester film has, at a wavelength of 550 nm, a biaxiality degree (NZ) represented by the following formula (3): 20 to?
<Formula 3>
NZ = (nx - nz) / (nx - ny)
(Where nx, ny and nz are the refractive indices of the polyester film in the x-, y- and z-axis directions, respectively). The polarizing plate according to claim 1, wherein the polyester film has a stretching ratio in the MD direction: a stretching ratio in the TD direction of 1: 1. delete delete The polarizing plate according to claim 1, wherein the polyester film is non-birefringent. The polarizing plate according to claim 1, wherein the polyester film is a film made of one or more resins selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate and polybutylene naphthalate. The polarizer according to claim 1, further comprising an optical film on a light incident surface of the polarizer. The polarizing plate according to claim 7, wherein the optical film is a retardation film. The optical film according to claim 7, wherein the optical film is at least one selected from the group consisting of cellulose, polyester, cyclic polyolefin, polycarbonate, polyether sulfone, polysulfone, polyamide, polyimide, polyolefin, Wherein the film is made of one or more resins selected from the group consisting of polyvinyl alcohol, polyvinyl chloride, and polyvinylidene chloride. Extruded polyester resin was simultaneously biaxially stretched in the MD direction and the TD direction so that the stretching ratio in the MD direction: TD direction was 1: 0.8 to 1: 1.2, thereby producing a polyester film,
And adhering the polyester film to the light output surface of the polarizer,
Wherein the polyester film has an in-plane retardation (Re) of 0 to 500 nm and a thickness direction retardation (Rth) represented by the following formula (2): 1,000 nm to 10,000 nm,
<Formula 1>
Re = (nx - ny) xd
(Where nx and ny are refractive indices of the polyester film in the x- and y-axis directions, respectively, and d is the thickness (unit: nm) of the polyester film)
<Formula 2>
Rth = ((nx + ny) / 2 - nz) xd
(Where nx, ny and nz are the refractive indices of the polyester film in the x-, y- and z-axis directions and d is the thickness (unit: nm) of the polyester film)
When the refractive index of the polyester film is 550 nm, the refractive index in the x-axis direction is nx, and the refractive index in the y-axis direction is ny, nx-ny is 0 to 0.1,
Wherein the polyester film has a biaxiality degree (NZ) of 20 to infinite represented by the following formula 3 at a wavelength of 550 nm:
<Formula 3>
NZ = (nx - nz) / (nx - ny)
(Where nx, ny and nz are the refractive indices of the polyester film in the x-, y- and z-axis directions, respectively). delete delete The method of producing a polarizing plate according to claim 10, wherein the polyester resin comprises at least one of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate. The method of manufacturing a polarizing plate according to claim 10, wherein the stretching ratio in the MD direction is 1: 1 in the TD direction. The method of manufacturing a polarizing plate according to claim 10, further comprising adhering an optical film to the light incident surface of the polarizer. A liquid crystal display device comprising the polarizing plate of any one of claims 1, 2, and 5 to 9.

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