Highly durable polarizing plate and display device comprising the same

Patent metadata

Field	Value
Publication number	US-9772436-B2
Application number	US-201615041611-A
Country	US
Kind code	B2
Filing date	Feb 11, 2016
Priority date	Feb 11, 2015
Publication date	Sep 26, 2017
Grant date	Sep 26, 2017

Abstract

A highly durable polarizing plate and a display device including the same are provided. In the highly durable polarizing plate, sticking agent having different storage modulus are formed on top and bottom surfaces of a λ/4 retardation film. Such a highly durable polarizing plate can be attached to LCDs and OLEDs to realize high-quality screens due to a small change in retardation value under environments for reliability evaluation of heat resistance and wet-heat resistance.

First claim

The invention claimed is:

1. A polarizing plate comprising a first sticking agent layer, a λ/4 retardation film, a second sticking agent layer, and a polarizing film, which are stacked from a lower portion of the polarizing plate;
wherein the first sticking agent layer and the λ/4 retardation film are bonded to each other, the λ/4 retardation film and the second sticking agent layer are bonded to each other, the first sticking agent layer has a storage modulus G1′ of 3.5×10 5 to 7.0×10 5 Pa, and the second sticking agent layer has a storage modulus G2′ of 1.1×10 6 to 1.5×10 6 Pa.

2. The polarizing plate of claim 1 , wherein the first sticking agent layer has a storage modulus G1′ of 3.5×10 5 to 6.7×10 5 Pa, and the second sticking agent layer has a storage modulus G2′ of 1.2×10 6 to 1.4×10 6 Pa.

3. The polarizing plate of claim 1 , wherein each of the first sticking agent layer and the second sticking agent layer has a thickness of 3 to 100 μm.

4. The polarizing plate of claim 1 , wherein the first sticking agent layer has a thickness of 10 to 50 and the second sticking agent layer has a thickness of 5 to 30 μm.

5. The polarizing plate of claim 1 , wherein the λ/4 retardation film is a λ/4 retardation film having a liquid crystal coating layer formed by coating.

6. The polarizing plate of claim 1 , wherein the λ/4 retardation film is an inverse-wavelength dispersible film having a

R
o

⁡

(

450
⁢

⁢
nm

)

R
o

⁡

(

550
⁢

⁢
nm

)

value of 0.7 to 0.99 with respect to a front retardation value R o .

7. The polarizing plate of claim 1 , wherein the λ/4 retardation film is a flat-wavelength dispersible film having a

R
o

⁡

(

450
⁢

⁢
nm

)

R
o

⁡

(

550
⁢

⁢
nm

)

value of 0.99 to 1.01 with respect to a front retardation value R o .

8. The polarizing plate of claim 1 , wherein the λ/4 retardation film is a normal-wavelength dispersible film having a

R
o

⁡

(

450
⁢

⁢
nm

)

R
o

⁡

(

550
⁢

⁢
nm

)

value of 1.01 to 2 with respect to a front retardation value R o .

9. The polarizing plate of claim 1 , wherein the λ/4 retardation film has a thickness-direction retardation value R th of 40 to 180 nm.

10. The polarizing plate of claim 1 , wherein the λ/4 retardation film has a front retardation value R o of 110 to 180 nm.

11. The polarizing plate of claim 1 , wherein the polarizing film has a stacked structure comprising a polarizer and a protective film formed on at least one surface of the polarizer.

12. The polarizing plate of claim 1 , further comprising a zero retardation film formed to come in contact with at least one layer selected from the group consisting of the first sticking agent layer and the second sticking agent layer.

13. A display device comprising the polarizing plate as defined in claim 1 .

Assignees

• Dongwoo Fine Chem Co Ltd

Inventors

• Lee Eun Ok
• Kim Yun Seong

Classifications

• 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

• G02B5/3016

  involving passive liquid crystal elements (optical properties of liquid crystals G02F1/0063; polarising elements associated with active liquid crystal devices G02F1/133528) · CPC title

• G02B1/14

  Protective coatings, e.g. hard coatings · CPC title

• G02F1/133528

  Polarisers · CPC title

• G02F1/13362

  providing polarized light, e.g. by converting a polarisation component into another one · CPC title