KR102084118B1 - Polarizing plate for oled and optical display apparatus comprising the same - Google Patents

Abstract

The present invention is a polarizer; A protective film formed on the polarizer; And a polarizing plate for an OLED including a laminate of a λ / 4 reverse wavelength dispersion retardation film and a positive C plate formed under the polarizer, and an optical display device including the same.

Description

POLARIZING PLATE FOR OLED AND OPTICAL DISPLAY APPARATUS COMPRISING THE SAME}

The present invention relates to a polarizing plate for an organic light emitting diode (OLED) and an optical display device including the same.

In the OLED display device, light generated from the self-luminous body and external natural light (external light) coming from the outside and reflected on the internal reflector may interfere with each other, thereby degrading the performance of the display. In order to suppress this, the OLED display device includes a polarizing plate.

In general, the polarizing plate for OLED is oriented such that the absorption axis of the polarizer and the optical axis (absorption axis) of the retardation compensation film are inclined. As a result, the waveform of external light reflected by the internal reflector is rotated to have a function as an antireflection filter. However, such an asymmetrical orientation of the absorption axis of the polarizer and the optical axis of the retardation compensation film may cause side color shifts during OLED driving.

As a method for solving such a side color shift phenomenon, a configuration in which a polarizing plate includes two retardation films, a biaxially stretched retardation compensation film, a reverse wavelength dispersion film, or a liquid crystal type retardation compensation film has been attempted. Currently commercially available polarizing plates for OLEDs include a λ / 4 reverse wavelength dispersion retardation compensation film made of polycarbonate, but improvements to the side color shift phenomenon are insufficient. That is, as the angle of incidence increases with respect to the front face, the color changes to a blue or purple color or reflectance increases according to the azimuth angle. This is because the optical path of external light on the side is different from the front side depending on the incident angle, resulting in phase delay of RGB.

In this regard, Korean Patent Publication No. 2010-0008203 discloses a polarizer, an upper transparent support attached to an upper surface of the polarizer, a compensation film attached to a lower surface of the polarizer, and a pressure-sensitive adhesive for laminating the compensation film and a liquid crystal cell. A polarizing plate comprising a layer is disclosed.

SUMMARY OF THE INVENTION An object of the present invention is to provide an OLED polarizing plate which improves the OLED side color shift phenomenon in which the reflection color is changed according to the side direction.

Another object of the present invention is to provide an OLED polarizing plate that can be thinned.

Still another object of the present invention is to provide an optical display device including the OLED polarizing plate.

The polarizing plate for OLED which is one aspect of this invention is a polarizer; A protective film formed on the polarizer; And it may include a laminate of the λ / 4 reverse wavelength dispersion retardation film and the positive C plate formed on the lower portion of the polarizer.

An optical display device according to another aspect of the present invention may include the polarizing plate for OLED.

The present invention provides an OLED polarizing plate capable of thinning SILM and solving the OLED side color shift phenomenon in which the reflection color is changed according to the lateral direction in a polarizing plate in which the absorption axis of the polarizer and the optical axis of the retardation film are inclined.

1 is a cross-sectional view of a polarizing plate for an OLED of an embodiment of the present invention.
2 is a cross-sectional view of a polarizing plate for an OLED of another embodiment of the present invention.
3 is a cross-sectional view of a polarizing plate for OLED of another embodiment of the present invention.
4 is a cross-sectional view of an optical display device according to an embodiment of the present invention.
5 is a front phase difference change value (dotted line: retardation with respect to absorption axis of retardation film, solid line: retardation with respect to transmission axis of retardation film) at −75 ° to + 75 ° incident angles of the laminate of Example 1 at a wavelength of 550 nm .
6 is a front phase difference change value (dotted line: phase difference with respect to the absorption axis of a phase difference film, solid line: phase difference film) at a −75 ° to + 75 ° incident angle of the λ / 4 reverse wavelength dispersion retardation compensation film of Comparative Example 1 at a wavelength of 550 nm. Phase difference with respect to the transmission axis.
FIG. 7 is the λ / 4 reverse wavelength dispersion of Comparative Example 1 at Ro (solid line) and lateral azimuthal angle (tilt, unit: °) at a wavelength of 550 nm of the laminate of Example 1 at lateral azimuthal angle (tilt); Ro (dotted line) in wavelength 550nm of retardation compensation film.
FIG. 8 is the λ / 4 reverse wavelength dispersion phase difference of Comparative Example 1 at a wavelength of 550 nm of the laminate of Example 1 at a side azimuth angle (tilt) and a side azimuth angle (tilt) at a wavelength of 550 nm. Rth (dotted line) at the wavelength of 550 nm of a compensation film.
9 is a result of color shift according to the side azimuth angle (Angle, unit: °) of the polarizing plate of Example 1.
10 is a result of color shift according to the side azimuth angle (Angle, unit: °) of the polarizing plate of Comparative Example 1.

In the present specification, 'upper' and 'lower' are defined on the basis of the drawings for convenience, and 'upper' may be changed to 'lower' and 'upper' according to a viewing time.

The polarizing plate for OLED which is one aspect of this invention is a polarizer; A protective film formed on the polarizer; And it may include a laminate of the λ / 4 reverse wavelength dispersion retardation film and the positive C plate formed on the lower portion of the polarizer.

An OLED panel may be laminated by an adhesive under the laminate.

1 and 2 are cross-sectional views of the polarizing plate for an OLED of an embodiment of the present invention.

Referring to FIG. 1, an OLED polarizing plate 100 may include a polarizer 105; A protective film 110 laminated on an upper surface of the polarizer 105; A λ / 4 reverse wavelength-dispersive retardation film 115 laminated on the bottom surface of the polarizer 105; And a positive C plate 120 stacked on a lower surface of the λ / 4 reverse wavelength dispersion retardation film 115.

2, a polarizer 200 for an OLED includes a polarizer 205; A protective film 210 laminated on an upper surface of the polarizer 205; A positive C plate 220 stacked on a bottom surface of the polarizer 205; And a λ / 4 reverse wavelength dispersible retardation film 215 stacked on the bottom surface of the positive C plate 220.

1 and 2, the stacking order of the λ / 4 reverse wavelength dispersible retardation film and the positive C plate is not limited among the polarizing plates for OLED. That is, the lower surface of the polarizer may be in contact with the λ / 4 reverse wavelength dispersion retardation film of the laminate. Alternatively, the lower surface of the polarizer may be in contact with the positive C plate of the laminate.

In the laminate, the difference in retardation value is minimized in the total orientation of the side surfaces compared to the λ / 4 reverse wavelength dispersion retardation film alone, thereby eliminating the lateral color shift phenomenon in which the color changes in the lateral direction. That is, the positive C plate may improve side color shift by minimizing a phase retardation occurring when the optical axis (absorption axis) of the λ / 4 reverse wavelength dispersion retardation film and the absorption axis of the polarizer are inclined.

In a specific embodiment, assuming that the polarizing plate is stacked on the OLED panel, the front viewing angle is 0 °, the left viewing direction is '-' relative to the front surface, and the right viewing direction is '+'. At -75 ° to 0 °, 0 ° to + 75 °, the laminate may have a phase retardation Ro of 130 nm to 145 nm with respect to the transmission axis of the retardation film. In addition, the laminate may have a phase retardation Ro of 145 nm to 165 nm with respect to an absorption axis of the retardation film at a side viewing angle of −75 ° to 0 ° and 0 ° to + 75 ° at a wavelength of 550 nm.

The laminate may have a front retardation (Ro) of 144.4 nm to 150 nm, preferably 144.4 nm to 145 nm at a wavelength of 550 nm. In the above range, there may be an effect of improving the side color shift.

The laminate may have a phase difference (Rth _A ) of 0 nm to 300 nm in the thickness direction represented by Equation 1 at a wavelength of 550 nm, and a degree of biaxiality (Nz _A ) represented by Equation 2 below 0.8. In the above range, Lateral color shifts can be improved:

<Equation 1>

Rth _A = ((nx _A + ny _A ) / 2-nz _A ) × d _A

<Equation 2>

Nz _A = (nx _A -nz _A ) / (nx _A -ny _A )

(In the above, nx _A , ny _A , nz _A are the refractive index in the x-axis direction, the refractive index in the y-axis direction and the refractive index in the z-axis direction, respectively, and d _A is the thickness (unit: nm).

Preferably, Rth _A may be 0 nm to 150 nm, Nz _A may be 0.5 to 0.8, more preferably Rth _A may be 0 nm to 30 nm, and Nz _A may be 0.6 to 0.7.

The laminate may be divided into an x-axis direction in the longitudinal direction (MD, machine direction) of the retardation film, a y-axis direction in the transverse direction (TD), and a z-axis direction in the thickness direction.

In the laminate, a λ / 4 reverse wavelength dispersion retardation film and a positive C plate may be laminated by an adhesive layer. The adhesive layer may be formed of an acrylic adhesive or the like, but is not limited thereto.

The laminate may have a thickness of 5 μm to 100 μm. In the above range, it can be used for the polarizing plate applications.

The detailed component of the polarizing plate for OLEDs of this invention is demonstrated in detail.

Polarizer

The polarizer may include a conventional polarizer having polarization performance. In one embodiment, the polarizer is provided with a function of absorbing and aligning a dichroic dye to a polyvinyl alcohol-based resin to absorb linearly polarized light having a vibration surface in a specific direction, and to transmit linearly polarized light having a vibration surface in a direction orthogonal thereto. Linear polarizers can be used. The dichroic dye may include iodine or a dichroic organic dye.

Typically, the polarizer can be produced by uniaxial stretching of a polyvinyl alcohol-based resin film, dyeing with a dichroic dye, and boric acid treatment after dyeing.

The polarizer may have a thickness of about 4 μm to about 30 μm.

Protective film

The protective film is a film made of a transparent resin, which is conventionally used as a protective film of a polarizer, and is not particularly limited. In one embodiment, the protective film is a cellulose-based polyester, cyclic polyolefin-based, polycarbonate-based, polyether sulfone-based, polysulfone-based, polyamide-based, polyimide-based, polyolefin-based, including triacetyl cellulose-based, etc. It may be a film made of one or more of polyarylate, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride.

The protective film has a thickness of 5㎛ ~ 100㎛, preferably 5 μm to 80 μm. In the above range, it can be used as a polarizing plate when laminated on the polarizer.

The protective film may be laminated on the polarizer by an adhesive layer. In an embodiment, the adhesive layer may include an adhesive layer formed of a water-based adhesive, a pressure-sensitive adhesive, or a UV-based adhesive. For example, it may be formed of a polyvinyl alcohol-based water-based adhesive.

One surface of the protective film, for example, the upper portion of the protective film may further include a functional layer. The functional layer may be a hard coat layer, an antireflection layer, or the like. In particular, the hard coating layer can improve the hardness decrease of the polarizing plate by improving the hardness of the protective film. In embodiments, the functional layer may have a thickness of 1 μm to 50 μm.

λ / 4 reverse wavelength dispersion retardation film

The λ / 4 reverse wavelength dispersion retardation film may be a film having reverse wavelength dispersion while having a plane direction λ / 4 retardation value. The 'reverse wavelength dispersion' may mean a tendency to increase as the wavelength increases with respect to the front retardation value Ro at the reference wavelength or Nz, or the front retardation value at wavelength 380 nm to 780 nm. The reference wavelength may be 550 nm.

The λ / 4 reverse wavelength dispersion retardation film may be combined with a polarizer to provide a function as an antireflection filter for an OLED.

The retardation film has a biaxial degree (Nz _B ) represented by Equation 4 at a wavelength of 550 nm, with a phase retardation Ro of 100 nm to 200 nm, and a thickness direction retardation Rth _B represented by Equation 3 0 nm to 300 nm In-plane retardation (Re _B ) represented by 0.8 to 1.2 and Equation 5 may be 100 nm to 200 nm:

<Equation 3>

Rth _B = ((nx _B + ny _B ) / 2-nz _B ) × d _B

<Equation 4>

Nz _B = (nx _B -nz _B ) / (nx _B -ny _B )

<Equation 5>

Re _B = (nx _B -ny _B ) × d _B

(In the above, nx _B , ny _B , nz _B are the refractive index in the x-axis direction, the refractive index in the y-axis direction and the z-axis refractive index, respectively, and d _B is the thickness of the retardation film (unit: nm).

The retardation film may be divided into an x-axis direction that is a longitudinal direction (MD), a y-direction that is a transverse direction (TD), and a z-axis direction that is a thickness direction of the retardation film.

In a specific embodiment, assuming that the polarizing plate including the retardation film is laminated on the OLED panel, when the front viewing angle is 0 °, the left direction is '-' and the right direction is '+' based on the front surface. The retardation film may have a phase retardation Ro of 45 nm to 145 nm with respect to the transmission axis of the retardation film at a side viewing angle of −75 ° to 0 ° and 0 ° to + 75 ° at a wavelength of 550 nm.

The retardation film may have a phase retardation Ro of 145 nm to 200 nm with respect to an absorption axis of the retardation film at a side viewing angle of −75 ° to 0 ° and 0 ° to + 75 ° at a wavelength of 550 nm.

In the retardation film, the absorption axis of the polarizer and the optical axis (absorption axis) of the retardation film are 43 ° to 47 ° to each other such that an angle between the absorption axis and the optical axis is 43 ° to 47 ° or 133 ° to 137 °. Or inclined orientation from 133 ° to 137 °.

The retardation film may be laminated on the polarizer by an adhesive layer. In an embodiment, the adhesive layer may include an adhesive layer formed of a water-based adhesive, a pressure-sensitive adhesive, or a UV-based adhesive. For example, it may be formed of a polyvinyl alcohol-based water-based adhesive.

The retardation film may be a film made of a transparent resin. In embodiments, the retardation film may include a film including at least one of polycarbonate (PC) resin, cycloolefin polymer (COP) resin, acrylic resin, cellulose resin.

The retardation film may have a thickness of 50 to 100 μm, preferably 50 to 75 μm. In the above range, it can be used for the polarizing plate applications.

Positive C Plate

Positive C plate means a positive uniaxial optical element whose refractive index distribution satisfies nz _C > nx _C = ny _C. The retardation film used as the positive C plate may be a solidified layer or a cured layer of the liquid crystal composition containing a liquid crystal compound.

The positive C plate may have an in-plane phase difference Re _C represented by Equation 6 below 5 nm and a thickness direction phase difference Rth _C represented by Equation 7 below −300 to 0 nm at a wavelength of 550 nm:

<Equation 6>

Re _C = (nx _C -ny _C ) xd _C

<Equation 7>

Rth _C = ((nx _C + ny _C ) / 2-nz _C ) × d _C

(In the above, nx _C , ny _C , nz _C are the refractive index in the x-axis direction, the refractive index in the y-axis direction and the z-axis refractive index, respectively, and d _C is the thickness of the positive C plate ( Unit: nm).

Preferably Re _C may be 0 ~ 5nm, Rth _C may be -150 ~ -50nm.

The positive C plate is a liquid crystal oriented film, and may be manufactured and used by commercially available products or by conventional methods known to those skilled in the art.

The positive C plate may be divided into an x-axis direction that is a liquid crystal coating direction, a y-axis direction that is a direction perpendicular to the liquid crystal coating direction, and a z-axis direction that is a thickness direction.

The positive C plate may be laminated to the polarizer by an adhesive layer. In an embodiment, the adhesive layer may include an adhesive layer formed of a water-based adhesive, a pressure-sensitive adhesive, or a UV-based adhesive. For example, it may be formed of a polyvinyl alcohol-based water-based adhesive.

The positive C plate may have a thickness of 0.1 to 10 μm, preferably 1 to 5 μm. In the above range, it can be used for the polarizing plate applications.

The polarizing plate may further include an isotropic film as a protective film between the polarizer and the laminate.

Referring to FIG. 3, an OLED polarizer 300 may include a polarizer 305; A protective film 310 laminated on an upper surface of the polarizer 305; An isotropic film 325 laminated on the lower surface of the polarizer 305; A λ / 4 reverse wavelength dispersible retardation film 315 laminated on a lower surface of the isotropic film 325; And a positive C plate 320 stacked on the lower surface of the λ / 4 reverse wavelength dispersion retardation film 315.

The isotropic film is not limited as long as the film can protect the polarizer without affecting the phase difference between the λ / 4 reverse wavelength dispersion retardation film and the positive C plate.

In an embodiment, the isotropic film can be an unstretched transparent film. For example, cyclic polyolefin (COP) type, cellulose type, polyester type, polycarbonate type, polyether sulfone type, polysulfone type, polyamide type, polyimide type, polyolefin type, polyarylate type, polyvinyl alcohol The film may be made of at least one of polyvinyl chloride-based and polyvinylidene chloride-based materials.

The isotropic film may have a thickness of 5 μm to 100 μm, preferably 5 μm to 80 μm. In the above range, it can be used for the polarizing plate applications.

The polarizing plate may have a polarization degree of 90% or more, preferably 90 to 99.99%. In the above range, it can be used for polarizer applications in OLED devices.

The polarizing plate has a transmittance at a wavelength of 550 nm. 38% or more, preferably 40 to 49%. In the above range, it can be used for polarizer applications in OLED devices.

The polarizing plate may have a thickness of 50 μm to 200 μm, preferably 80 μm to 130 μm. In the above range, it can be used for the polarizing plate applications.

An optical display device according to another aspect of the present invention may include the polarizing plate for OLED. The optical display device may include, but is not limited to, an organic light emitting diode (OLED) display device.

4 is a cross-sectional view of an optical display device according to an embodiment of the present invention.

Referring to FIG. 4, the optical display device 400 includes an OLED panel 405; A polarizing plate 100 stacked on an upper surface of the OLED panel 405; And an adhesive layer 410 formed between the polarizing plate 100 and the OLED panel 405.

Hereinafter, the configuration and operation of the present invention through the preferred embodiment of the present invention will be described in more detail. However, it is presented as a preferred example of the present invention and should not be construed as limiting the present invention by any means.

Example 1

The polyvinyl alcohol film (PS # 60, Japan Kuraray Co., Ltd., 60 micrometers in thickness before extending | stretching) was stretched 6 times in 55 degreeC iodine aqueous solution, and the polarizer of 45% of the transmittance | permeability was obtained. A hard-acetylated triacetyl cellulose film (HC TAC (DNP, CHP2S), thickness: 30 μm) was attached to the polarizer with a polyvinyl alcohol adhesive.

Positive C plate (JX, NV80, Re: 0nm at wavelength 550nm, Rth: -78nm, thickness: 2㎛) and λ / 4 reverse wavelength dispersible retardation compensation film (Teijin, polycarbonate film, Re: at wavelength 550nm 145 nm, Rth: 100 nm, Nz: 1.2, thickness: 50 µm) were bonded together with an acrylic adhesive to prepare a laminate. The optical axis (absorption axis) of the λ / 4 reverse wavelength dispersion retardation compensation film and the absorption axis of the polarizer are aligned to each other by 45 °, and the polarizer and the λ / 4 reverse wavelength dispersion retardation compensation film are contacted with an acrylic adhesive. The laminated body was stuck to the lower part of the polarizer, and the polarizing plate of FIG. 1 was produced.

Example 2

In Example 1, except that the polarizer and the positive C plate was in contact with each other, the same method was carried out to prepare a polarizing plate of FIG.

Comparative Example 1

The polyvinyl alcohol film (PS # 60, Japan Kuraray Co., Ltd., 60 micrometers in thickness before extending | stretching) was stretched 6 times in 55 degreeC iodine aqueous solution, and the polarizer of 45% of the transmittance | permeability was obtained. A hard-acetylated triacetyl cellulose film (HC TAC (DNP, CHP2S), thickness: 30 μm) was attached to the polarizer with a polyvinyl alcohol adhesive. Λ / 4 reverse wavelength dispersion retardation compensation film (Teijin, polycarbonate film, wavelength 550nm) such that the optical axis of the λ / 4 reverse wavelength dispersion retardation compensation film and the absorption axis of the polarizer are 45 ° below the polarizer. Re: 145nm, Rth: 100nm, Nz: 1.2) was bonded to the acrylic adhesive to prepare a polarizing plate.

Comparative Example 2

The polyvinyl alcohol film (PS # 60, Japan Kuraray Co., Ltd., 60 micrometers in thickness before extending | stretching) was stretched 6 times in 55 degreeC iodine aqueous solution, and the polarizer of 45% of the transmittance | permeability was obtained. A hard-acetylated triacetyl cellulose film (HC TAC (DNP, CHP2S), thickness: 30 μm) was attached to the polarizer with a polyvinyl alcohol adhesive. A positive C plate (JX, NV80, Re: 0nm at a wavelength of 550nm, Rth: -78nm) was attached to the lower part of the polarizer with an acrylic adhesive to prepare a polarizing plate.

It assembled to the polarizing plate single piece or OLED panel manufactured above, and evaluated the physical property, and the result is shown to FIGS. 5-10.

(1) Transmittance (Ts) and polarization degree (P.E): The polarizing plate was measured using V-7100 (JASCO, Japan).

(2) Phase difference characteristics: A stack of 50 mm x 50 mm (horizontal x vertical) positive C plates and a λ / 4 reverse wavelength dispersion retardation compensation film, or a plate of Axoscan apparatus for λ / 4 reverse wavelength dispersion retardation compensation film alone It mounted and measured the phase difference characteristic in wavelength 550nm.

(3) Reflectance and color shift: The polarizing plates were laminated on the OLED panel, and the reflectance and color change values were measured using a EZ-contrast three-dimensional measuring instrument (Eldim, France) at a lateral azimuth angle and a wavelength of 550 nm in a predetermined range.

division Polarizer Plate Thickness (㎛) Fragment transmittance (%) Polarization degree (%) reflectivity(%) Nz Remarks Example 1 112 44.8 99.2 4.8 0.67 - Example 2 112 44.8 99.2 4.8 0.67 - Comparative Example 1 107 44.8 99.2 5.0 1.2 - Comparative Example 2 57 44.8 99.2 25 0.5 Anti-reflective filter function

As shown in Table 1 and Figures 5 to 10, the polarizing plate of the present invention improved the side color by minimizing the phase difference value in the thickness direction at the side azimuth as shown in Figures 5 and 8, and minimizes the side color shift phenomenon. This can be seen through the results of FIG. 9.

On the other hand, in the polarizing plate of Comparative Example 1, which does not include the positive C plate, as shown in FIGS. 6 and 8, the phase difference value in the thickness direction in the side direction is significantly larger than that of the present invention, and the side color shift phenomenon may occur. This can be seen through the result of FIG. 10.

In addition, the polarizing plate of Comparative Example 2, which does not include the λ / 4 reverse wavelength dispersion retardation film, has a problem in that it does not express the function of the antireflection filter.

Simple modifications and changes of the present invention can be easily made by those skilled in the art, and all such modifications and changes can be seen to be included in the scope of the present invention.

Claims (16)

Polarizer; A protective film formed on the polarizer; And a polarizing plate for an OLED comprising a laminate of λ / 4 reverse wavelength dispersion retardation film and a positive C plate formed on the lower portion of the polarizer,
The laminate has a biaxiality degree (Nz _A ) of 0.6 to 0.8 represented by <Formula 2> at a wavelength of 550 nm,
<Equation 2>
Nz _A = (nx _A -nz _A ) / (nx _A -ny _A )
(In <Equation 2>, nx _A , ny _A , nz _A are the refractive index in the x-axis direction, the refractive index in the y-axis direction, and the refractive index in the z-axis direction of the laminate, respectively.
The laminate has a phase difference Rth _A of 0 nm to 30 nm in the thickness direction represented by the following Equation 1 at a wavelength of 550 nm,
<Equation 1>
Rth _A = ((nx _A + ny _A ) / 2-nz _A ) × d _A
(In <Equation 1>, nx _A , ny _A , nz _A are the refractive index in the x-axis direction, the refractive index in the y-axis direction, and the refractive index in the z-axis direction, respectively, and d _A is Thickness (in nm),
The positive C plate has a thickness direction phase difference Rth _C represented by the following Equation 7 at a wavelength of 550 nm of -150 nm to -70 nm:
<Equation 7>
Rth _C = ((nx _C + ny _C ) / 2-nz _C ) × d _C
In Equation 7, nx _C , ny _C , and nz _C are the refractive index in the x-axis direction, the refractive index in the y-axis direction, and the refractive index in the z-axis direction of the positive C plate, respectively, and d _C is positive C. The thickness of the plate (unit: nm),
The λ / 4 reverse wavelength dispersible retardation film is an in-plane retardation (Re _B ) represented by the following formula 5 is 145nm to 200nm, the thickness direction retardation (Rth _B ) represented by the following formula 3 is 100nm ~ 300nm, Polarizers for OLED:
<Equation 5>
Re _B = (nx _B -ny _B ) × d _B
In Equation 5, nx _B and ny _B are the refractive index in the x-axis direction and the refractive index in the y-axis direction of the λ / 4 reverse wavelength dispersion retardation film, respectively, and d _B is the λ / 4 reverse wavelength. Thickness of the dispersible retardation film (unit: nm),
<Equation 3>
Rth _B = ((nx _B + ny _B ) / 2-nz _B ) × d _B
In Equation 3, nx _B , ny _B , and nz _B are the refractive index in the x-axis direction, the refractive index in the y-axis direction, and the refractive index in the z-axis direction of the λ / 4 reverse wavelength dispersion retardation film, respectively. , d _B is the thickness (unit: nm) of the λ / 4 reverse wavelength dispersion retardation film.
The polarizing plate of claim 1, wherein the λ / 4 reverse wavelength dispersion retardation film is in contact with the polarizer.
The polarizing plate of claim 1, wherein the positive C plate is in contact with the polarizer.
delete delete The polarizing plate of claim 1, wherein the absorption axis of the polarizer and the optical axis (absorption axis) of the retardation film are oriented at 43 ° to 47 °, or 133 ° to 137 °.
The polarizing plate of claim 1, wherein the laminate has a thickness of 5 μm to 100 μm.
The polarizing plate of claim 1, wherein the λ / 4 reverse wavelength dispersion retardation film has a biaxial degree (Nz _B ) of 0.8 to 1.2 represented by <Formula 4>:
<Equation 4>
Nz _B = (nx _B -nz _B ) / (nx _B -ny _B )
In Equation 4, nx _B , ny _B , and nz _B are the refractive index in the x-axis direction, the refractive index in the y-axis direction, and the refractive index in the z-axis direction of the λ / 4 reverse wavelength dispersion retardation film, respectively. ).
The polarizing plate of claim 1, wherein the λ / 4 reverse wavelength dispersible retardation film comprises at least one of polycarbonate (PC) resin, cycloolefin polymer (COP) resin, acrylic resin, and cellulose resin.
The polarizing plate of claim 1, wherein the positive C plate has an in-plane retardation (Re _C ) of 5 nm or less represented by the following <Formula 6> at a wavelength of 550 nm:
<Equation 6>
Re _C = (nx _C -ny _C ) xd _C
In Equation 6, nx _C and ny _C are the refractive index in the x-axis direction and the refractive index in the y-axis direction of the positive C plate, respectively, and d _C is the thickness (unit: nm) of the positive C plate. ).
The method of claim 1, wherein the protective film is a triacetyl cellulose type, polyester type, cyclic olefin polymer type, polycarbonate type, polyether sulfone type, polysulfone type, polyamide type, polyimide type, polyolefin type, polya A polarizing plate for an OLED comprising at least one of a related system, a polyvinyl alcohol system, a polyvinyl chloride system, and a polyvinylidene chloride system.
The polarizing plate of claim 1, further comprising a hard coating layer on the protective film.
The polarizing plate for OLED according to claim 1, further comprising an isotropic film between the polarizer and the laminate.
The method of claim 13, wherein the isotropic film is a cyclic olefin polymer (COP), cellulose, polyester, polycarbonate, polyether sulfone, polysulfone, polyamide, polyimide, polyolefin, A polarizing plate for an OLED comprising at least one of polyarylate, polyvinyl alcohol, polyvinyl chloride, and polyvinylidene chloride.
The polarizing plate for OLED of claim 1, wherein the polarizing plate for OLED has a thickness of 80 μm to 130 μm.
An optical display device comprising the polarizing plate of any one of claims 1 to 3, 6 to 15.

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