Polarizing plate and method for manufacturing the same
A polarizing plate includes a polarizer and a protective film formed on at least one surface of the polarizer. A transverse direction (TD) shrinkage stress ratio SR A of the polarizing plate ranges from about 1% to about 10%, as calculated using Equation 1: SR A (%)=( S 1/ S 2)×100 (1) In Equation 1, S1 is the TD shrinkage stress of the protective film, and S2 is the TD shrinkage stress of the polarizer.
1. A polarizing plate comprising:
a polarizer having a first shrinkage stress in a transverse direction (TD); and
a protective film on at least one surface of the polarizer, the protective film having a second shrinkage stress in the TD, the second shrinkage stress being different from the first shrinkage stress,
wherein a TD shrinkage stress ratio SR A of the polarizing plate is about 1% to 10% as calculated by Equation 1:
SR A (%)=( S 1/ S 2)×100 (1)
wherein S1 is the second shrinkage stress of the protective film, and S2 is the first shrinkage stress of the polarizer.
2. The polarizing plate according to claim 1 , wherein the polarizing plate comprises the protective film on only an upper surface of the polarizer.
3. The polarizing plate according to claim 1 , wherein the first shrinkage stress S2 of the polarizer is about 0.5 N/10 mm to about 10.0 N/10 mm, and the second shrinkage stress S1 of the protective film is about 0.005 N/10 mm to about 1.0 N/10 mm.
4. The polarizing plate according to claim 1 , wherein the protective film comprises a polyester resin film, a cellulose resin film, a cyclic polyolefin resin film, a polycarbonate resin film, a polyethersulfone resin film, a polysulfone resin film, a polyamide resin film, a polyimide resin film, a non-cyclic polyolefin resin film, a polyarylate resin film, a polyvinyl alcohol resin film, a polyvinyl chloride resin film, or a polyvinylidene chloride resin film.
5. The polarizing plate according to claim 2 , further comprising:
a release film formed on a lower surface of the polarizer; and
an adhesive layer formed between the release film and the polarizer.
6. The polarizing plate according to claim 1 , further comprising:
an optical film comprising at least one of a surface protective film for the polarizing plate, a reflective film, an anti-reflective film, a diffusive film, a retardation film, or a brightness-enhancing film.
7. The polarizing plate according to claim 6 , wherein the polarizing plate has a TD shrinkage stress ratio SR B of about 1% to about 10% as calculated by Equation 2:
SR B (%)=( S 3/ S 2)×100 (2)
wherein S3 is a sum of TD shrinkage stresses of the optical films, and S2 is the first shrinkage stress of the polarizer.
8. The polarizing plate according to claim 1 , wherein the polarizing plate has a curl height of about +4.0 mm to about −4.0 mm, as measured at 23° C. and 55% RH.
9. A method of manufacturing the polarizing plate of claim 1 , comprising:
forming a stack body by stacking the protective film on one surface of the polarizer,
wherein the stack body has a transverse direction (TD) shrinkage stress ratio SR A of about 1% to 10%, as calculated by Equation 1:
SR A (%)=( S 1/ S 2)×100 (1)
wherein S1 is the second shrinkage stress of the protective film, and S2 is the first shrinkage stress of the polarizer.
10. The method according to claim 9 , wherein the polarizer is manufactured by dyeing and stretching a polyvinyl alcohol film.
11. The method according to claim 10 , wherein the polarizer is stretched to have an accumulated stretching ratio of about 5 to about 10.
12. The method according to claim 9 , further comprising:
attaching an optical film to one or both surfaces of the stack body.
13. The method according to claim 12 , wherein the polarizing plate has a TD shrinkage stress ratio SR B of about 1% to about 10%, as calculated by Equation 2:
SR B (%)=( S 3/ S 2)×100 (2)
wherein S3 is the sum of TD shrinkage stresses of the optical films, and S2 is the first shrinkage stress of the polarizer.