Polarizing plate and image display device comprising the same

1. A polarizing plate comprising:

a polarizer;

a first hard coating layer positioned on the polarizer, and containing a first binder resin comprising a (meth) acrylate-based (co) polymer;

a light transmitting substrate positioned on the side of the first hard coating layer opposite to the polarizer, and having a retardation of at least 3000 nm and in-plane birefringence; and

a second hard coating layer positioned on the side of the light transmitting substrate opposite to the first hard coating layer, and comprising a second binder resin and solid inorganic nanoparticles dispersed in the binder resin,

wherein an acute angle formed by a slow axis of the light transmitting substrate and an absorption axis of the polarizer is 5 to 85°,

wherein a thickness of the second hard coating layer is 45 μm or less,

wherein a thickness ratio of the first hard coating layer and the second hard coating layer is 1:0.5 to 1:0.63, and

wherein a rainbow change rate (ΔRb) of the polarizing plate calculated by Mathematical Formula 1 is 2.5% or less:

Δ Rb =(maximum reflectance at 450to 650 nm−minimum reflectance at 450to 650 nm)÷(mean reflectance at 450to 650 nm)×100,  [Mathematical Formula 1]

wherein a reflectance of the polarizing plate is measured under conditions of a 5º reflection mode, 2 nm slit width, and an analysis wavelength range of 380 to 780 nm, using a UV-Vis spectrometer, from which reflectance data at 450 to 650 nm are derived, and then a mean reflectance and difference between a maximum reflectance and a minimum reflectance at 450 to 650 nm are calculated and substituted in the Mathematical Formula 1.

2. The polarizing plate according to claim 1 ,

further comprising a quarter wave plate positioned on an opposite side of the polarizer to a side on which the first hard coating layer is positioned.

3. The polarizing plate according to claim 1 ,

wherein the light transmitting substrate is a polyethylene terephthalate (PET) film.

4. The polarizing plate according to claim 1 ,

wherein the light transmitting substrate has a difference in refractive indexes (n x −n y ) of at least 0.05, wherein n x is a refractive index of a slow axis direction and n y is a refractive index of a fast axis direction that is orthogonal to the slow axis direction.

5. The polarizing plate according to claim 1 ,

wherein the light transmitting substrate has a thickness of 10 to 500 μm.

6. The polarizing plate according to claim 1 ,

wherein a thickness ratio of the light transmitting substrate and the second hard coating layer is 1:0.1 to 1:1.

7. The polarizing plate according to claim 1 ,

wherein the (meth) acrylate-based (co) polymer of the first hard coating layer comprises monofunctional or multifunctional (meth) acrylate-based repeat units and urethane (meth) acrylate-based repeat units.

8. The polarizing plate according to claim 1 ,

wherein the second binder resin of the second hard coating layer comprises a photocurable resin and a (co) polymer having a weight average molecular weight of at least 10,000 g/mol.

9. The polarizing plate according to claim 2 ,

further comprising an adhesive layer positioned on an opposite side of the quarter wave plate to a side on which the polarizer is positioned.

10. The polarizing plate according to claim 1 ,

further comprising a low reflective layer positioned on the second hard coating layer, and comprising a binder resin and inorganic nanoparticles dispersed in the binder resin, or

an anti-fouling layer positioned on the second hard coating layer, and comprising a binder resin, solid inorganic nanoparticles dispersed in the binder resin, and a fluorine-based compound.

11. The polarizing plate according to claim 1 ,

wherein the polarizing plate has a pencil hardness under a 500 g load of 6H or more.

12. The polarizing plate according to claim 1 ,

wherein a laminate comprising the first hard coating layer, the light transmitting substrate, and the second hard coating layer has a pencil hardness under a 1 kg load of 6H or more.

13. An image display device comprising the polarizing plate of claim 1 .