US 12,235,484 B2
Polarizing plate
Eun Je Kim, Daejeon (KR); Je Hyuk Yoo, Daejeon (KR); Woo Yong Cho, Daejeon (KR); Yun Ki Park, Daejeon (KR); and Byeong Won Lee, Daejeon (KR)
Assigned to LG CHEM, LTD., Seoul (KR)
Appl. No. 17/635,657
Filed by LG CHEM, LTD., Seoul (KR)
PCT Filed Sep. 21, 2020, PCT No. PCT/KR2020/012675
§ 371(c)(1), (2) Date Feb. 15, 2022,
PCT Pub. No. WO2021/060779, PCT Pub. Date Apr. 1, 2021.
Claims priority of application No. 10-2019-0116807 (KR), filed on Sep. 23, 2019.
Prior Publication US 2022/0291436 A1, Sep. 15, 2022
Int. Cl. G02B 5/20 (2006.01); G02B 1/14 (2015.01); G02B 5/30 (2006.01); H10K 50/80 (2023.01)
CPC G02B 5/3083 (2013.01) [G02B 1/14 (2015.01); H10K 50/868 (2023.02)] 12 Claims
OG exemplary drawing
 
1. A polarizing plate comprising:
a polarizing film;
a hard coating layer formed on top of the polarizing film; and
a retardation layer formed on bottom of the polarizing film; and
an isotropic layer,
wherein the hard coating layer is formed directly on the top of the polarizing film without interposing layers,
wherein the retardation layer is formed on a first surface of the isotropic layer, and a second surface of the isotropic layer is attached to the polarizing film by an UV adhesive layer,
wherein the isotropic layer has an in-plane retardation of 20 nm or less and a thickness direction retardation of 20 nm or less,
wherein a reflective color value change (ΔE*ab) according to Equation 4 below is 10 or less:
ΔE*ab=[(ΔL*)2+(Δa*)2+(Δb*)2]1/2  [Equation 4]
wherein, ΔL* is L*a-L*i, Δa* is a*a-a*i, Δb* is b*a-b*i, and L*a, a*a and b*a are color coordinates before exposing the polarizing plate to light having a wavelength of 420 nm in a light quantity of 0.75 to 0.85 W/m2 at a temperature of 25° C. for 50 hours, and L*i, a*i and b*i are color coordinates after exposing the polarizing plate to light having a wavelength of 420 nm in a light quantity of 0.75 to 0.85 W/m2 at a temperature of 25° C. for 50 hours.