Polarizing plate and optical display device comprising same

A polarizing plate comprising:

• a polarizer;
• and
• a first protective layer stacked on a first surface of the polarizer via a first bonding layer,
• wherein the first bonding layer has a pH of 1 to 3 and is formed of a bonding layer composition comprising an epoxy compound and a photocationic initiator, and the polarizing plate has a chrominance variation ΔE of 5.2 or less, as calculated by Equation 1:
• ΔE=[(ΔL)2+(Δa*)2+(Δb*)2]1/2, <Equation 1>
• where ΔL is L2−L1;
• Δa* is (a*)2−(a*)1;
• and Δb* is (b*)2−(b*)1, in which L1 is an L value of the polarizing plate before the polarizing plate is left at 95° C. or 60° C. and 95% RH for 500 hours;
• L2 is an L value of the polarizing plate after the polarizing plate is left at 95° C. or 60° C. and 95% RH for 500 hours;
• (a*)1 is an a* value of the polarizing plate before the polarizing plate is left at 95° C. or 60° C. and 95% RH for 500 hours;
• (a*)2 is an a* value of the polarizing plate after the polarizing plate is left at 95° C. or 60° C. and 95% RH for 500 hours;
• (b*)1 is a b* value of the polarizing plate before the polarizing plate is left at 95° C. or 60° C. and 95% RH for 500 hours;
• and (b*)2 is a b* value of the polarizing plate after the polarizing plate is left at 95° C. or 60° C. and 95% RH for 500 hours, and
• wherein the polarizing plate has a light transmittance variation ratio of 1.5% or less, as calculated by Equation 4:
• Light transmittance variation ratio=|T2−T1|/T1×100, <Equation 4>
• where T1 is a light transmittance of the polarizing plate measured at a wavelength of 380 nm to 780 nm before the polarizing plate is left at 95° C. or 60° C. and 95% RH for 500 hours, and T2 is a light transmittance of the polarizing plate measured at a wavelength of 380 nm to 780 nm after the polarizing plate is left at 95° C. or 60° C. and 95% RH for 500 hours.