Polarizing plate and liquid crystal display including the same

Patent metadata

Field	Value
Publication number	US-2016146980-A1
Application number	US-201514952795-A
Country	US
Kind code	A1
Filing date	Nov 25, 2015
Priority date	Nov 26, 2014
Publication date	May 26, 2016
Grant date	—

Abstract

A polarizing plate and a liquid crystal display including the polarizing plate include: a polarizer; and a surface protective film on a first surface of the polarizer, and the surface protective film includes a first protective film on the first surface of the polarizer, and a primer layer on at least one surface of the first protective film, a refractive index ratio of the first protective film to the primer layer satisfying the equation: 0.6<R 1 /R 2 <1.0, where R 1 is an index of refraction of the primer layer, and R 2 is an index of refraction of the first protective film, and the first protective film has an in-plane retardation (Re) of about 500 nm or less and an out-of-plane retardation (Rth) of about 10,000 nm or less at a wavelength of 550 nm.

First claim

What is claimed is:

1 . A polarizing plate comprising:
a polarizer; and a surface protective film on a first surface of the polarizer, wherein the surface protective film comprises a first protective film on the first surface of the polarizer, and a primer layer on at least one surface of the first protective film, a refractive index ratio of the first protective film to the primer layer satisfying Equation 1:
0.6< R 1 /R 2 <1.0,
where R 1 is an index of refraction of the primer layer and R 2 is an index of refraction of the first protective film, the first protective film having an in-plane retardation (Re) of about 500 nm or less and an out-of-plane retardation (Rth) of about 10,000 nm or less at a wavelength of 550 nm, as respectively represented by Equation 2:
Re =( nx−ny )× d,

and Equation 3:
Rth =(( nx+ny )/2− nz )× d,

where nx, ny, and nz are indices of refraction at a wavelength of 550 nm in the x-, y- and z-axis directions, respectively, of the first protective film, and d is a thickness of the first protective film (unit: nm).

2 . The polarizing plate according to claim 1 , wherein the primer layer has a thickness of about 5 nm to about 200 nm.

3 . The polarizing plate according to claim 1 , wherein the primer layer has an index of refraction of about 1.0 to about 1.6.

4 . The polarizing plate according to claim 1 , wherein the primer layer comprises silica particles.

5 . The polarizing plate according to claim 4 , wherein the silica particles have an average particle diameter of about 0.001 μm to about 10 μm.

6 . The polarizing plate according to claim 4 , wherein the silica particles are present in an amount of about 0.1 wt % to about 20 wt % in the primer layer.

7 . The polarizing plate according to claim 1 , wherein the first protective film has a ratio of machine direction (MD) elongation to transverse direction (TD) elongation of about 1:0.8 to about 1:1.2.

8 . The polarizing plate according to claim 1 , wherein the first protective film has a ratio of MD elongation to TD elongation of about 1:1 and a degree of biaxiality (NZ) of about 1.0 or more at a wavelength of 550 nm, as represented by Equation 4:
NZ =( nx−nz )/( nx−ny ), where nx, ny, and nz are indices of refraction at a wavelength of 550 nm in the x-, y- and z-axis directions, respectively, of the first protective film.

9 . The polarizing plate according to claim 1 , wherein the first protective film has nx-ny of about 0 to about 0.1, where nx is an index of refraction in the x-axis direction and ny is an index of refraction in the y-axis direction, and a degree of biaxiality (NZ) of about 5.0 or more, as represented by Equation 4:
NZ =( nx−nz )/( nx−ny ), where nx, ny, and nz are indices of refraction at a wavelength of 550 nm in the x-, y- and z-axis directions, respectively, of the first protective film.

10 . The polarizing plate according to claim 1 , wherein the polarizing plate has a variation rate of transmittance of about 0.1% to about 1.8%, as represented by Equation 5:
Variation rate of transmittance (%)=( T B −T A )/ T A ×100,
where T A is an initial transmittance of the polarizing plate, and T B is a transmittance of the polarizing plate after being maintained at 85° C. for 500 hours.

11 . The polarizing plate according to claim 1 , wherein the surface protective film has a transmittance of about 92% or greater.

12 . The polarizing plate according to claim 1 , wherein the first protective film is a non-birefringent film.

13 . The polarizing plate according to claim 1 , wherein the first protective film comprises at least one resin selected from the group consisting of polyester resins, (meth)acrylic resins, and cyclic polyolefin (COP) resins.

14 . The polarizing plate according to claim 1 , further comprising a second protective film on a second surface of the polarizer opposite the first surface.

15 . The polarizing plate according to claim 14 , wherein the second protective film comprises at least one resin selected from the group consisting of cellulose resins, polyester resins, cyclic polyolefin resins, polycarbonate resins, polyethersulfone resins, polysulfone resins, polyamide resins, polyimide resins, polyolefin resins, polyarylate resins, polyvinyl alcohol resins, polyvinyl chloride resins, and polyvinylidene chloride resins.

16 . A liquid crystal display comprising the polarizing plate according to claim 1 .

Assignees

• Samsung Sdi Co Ltd

Inventors

• Shin Kwang Ho
• Park Eun Su
• Shin Dong Yoon

Classifications

• G02F1/133528 Primary

  Polarisers · CPC title

• G02B5/3083

  Birefringent or phase retarding elements (G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001) · CPC title

• G02B1/18 Primary

  Coatings for keeping optical surfaces clean, e.g. hydrophobic or photo-catalytic films (G02B1/16 takes precedence) · CPC title

• G02F1/13363

  Birefringent elements, e.g. for optical compensation · CPC title

• G02B5/30 Primary

  Polarising elements (light-modulating devices with active elements G02F1/00) · CPC title