Polarizing plate and optical display including the same
A polarizing plate includes a polarizer, and a protective film on one side of the polarizer and including a reverse dispersion liquid crystal coating layer having λ/4 retardation. An optical display panel includes the polarizing plate. The polarizing plate has a depolarization function and allows for viewing of the display panel through polarizing sunglasses.
1. A polarizing plate comprising:
a first polarizer;
a first protective film on a first side of the first polarizer; and
a reverse dispersion liquid crystal coating layer on the first protective film, the reverse dispersion coating layer being bonded to the first polarizer between the first polarizer and the first protective film,
wherein the reverse dispersion liquid crystal coating layer has an in-plane retardation (Re) of about 100 nm to about 170 nm at a wavelength of 550 nm, as calculated using Equation 1:
Re=( nx−ny )× d, Equation 1
wherein nx and ny are refractive indices in x- and y-axis directions, respectively, and d is a thickness of the reverse dispersion liquid crystal coating layer in nm.
2. The polarizing plate according to claim 1 , wherein the reverse dispersion liquid crystal coating layer has λ/4 retardation.
3. The polarizing plate according to claim 1 , wherein the reverse dispersion liquid crystal coating layer has a thickness of about 0.5 μm to about 10 μm.
4. The polarizing plate according to claim 1 , wherein the first protective film comprises a material selected from the group consisting of cellulose, polyester, cyclic polyolefin, polycarbonate, polyether sulfone, polysulfone, polyamide, polyimide, polyolefin, polyarylate, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride films, and combinations thereof.
5. The polarizing plate according to claim 1 , further comprising a hard coating layer on a side of the first protective film opposite from the reverse dispersion liquid crystal coating layer.
6. The polarizing plate according to claim 1 , further comprising a λ/2 retardation layer between the first protective film and the reverse dispersion liquid crystal coating layer.
7. The polarizing plate according to claim 6 , wherein the λ/2 retardation layer has an in-plane retardation (Re) of about 240 nm to about 300 nm at a wavelength of 550 nm, as calculated using Equation 3:
Re=( nx−ny )× d, Equation 3
wherein nx and ny are refractive indices in x- and y-axis directions, respectively, and d is a thickness of the λ/2 retardation layer in nm.
8. The polarizing plate according to claim 6 , wherein the λ/2 retardation layer is a liquid crystal coating layer or a film.
9. The polarizing plate according to claim 6 , wherein the λ/2 retardation layer has a thickness of about 0.5 μm to about 70 μm.
10. The polarizing plate according to claim 1 , further comprising a second protective film on a second side of the first polarizer, opposite from the first side.
11. The polarizing plate according to claim 10 , wherein the second protective film comprises a material selected from the group consisting of cellulose, polyester, cyclic polyolefin, polycarbonate, polyether sulfone, polysulfone, polyamide, polyimide, polyolefin, polyarylate, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride films, and combinations thereof.
12. An optical display comprising:
a display panel;
a first polarizing plate on a first side of the display panel; and
a second polarizing plate between a second side of the display panel and a backlight unit,
wherein the first polarizing plate is the polarizing plate according to claim 1 .