Polyene polarizer having specified dichroic ratio, method for manufacturing same, and polarizing plate and optical display device comprising same
The present invention relates to a polyene polarizer having an order parameter (S) of about 0.9-1 inclusive and a transmittance of about 43-100% inclusive, a method for manufacturing a polyene polarizer, which can stably produce a thin polyene polarizer having a high transmittance, a high degree of polarization and a high order parameter (S) value, and a polarizing plate and an optical display device each comprising the polyene polarizer.
1. A polyene polarizer, the polyene polarizer itself having an order parameter (S) from about 0.9 or more and 1 or less as represented by Equation 1, a transmittance from about 43% or more and 100% or less, and a dichroic ratio of 29 or greater to less than 50:
Order parameter( S )=( Rd− 1)/( Rd+ 2) <Equation 1>
wherein Rd is calculated by Equation 2 or 3;
Rd =log( Tc )/log( Tp ) <Equation 2>
wherein Tc is an orthogonal transmittance of the polyene polarizer (unit: %), and Tp is a parallel transmittance thereof (unit: %); and
Rd =log( Ts/ 100×(1− V/ 100))/log( Ts/ 100×(1+ V/ 100)) <Equation 3>
wherein Ts is a transmittance of a single polyene polarizer (unit: %), and V is a degree of polarization of the single polyene polarizer (unit: %).
2. A polyene polarizer, the polyene polarizer itself having an order parameter (S) from about 0.9 or more and 1 or less as represented by Equation 1, a thickness of about greater than 0 and 10 μm or less, and a dichroic ratio of 29 or greater to less than 50:
Order parameter( S )=( Rd− 1)/( Rd+ 2) <Equation 1>
wherein Rd is calculated by Equation 2 or 3;
Rd =log( Tc )/log( Tp ) <Equation 2>
wherein Tc is an orthogonal transmittance of the polyene polarizer (unit: %), and Tp is a parallel transmittance thereof (unit: %); and
Rd =log( Ts/ 100×(1− V/ 100))/log( Ts/ 100×(1+ V/ 100)) <Equation 3>
wherein Ts is a transmittance of a single polyene polarizer (unit: %), and V is a degree of polarization of the single polyene polarizer (unit: %).
3. The polyene polarizer according to claim 1 , wherein the polarizer itself has a degree of polarization of about 96% or more to 99.99% or less.
4. A method for preparing the polyene polarizer according to claim 1 , the method comprising:
performing dehydration and dry stretching of a polyvinyl alcohol film formed of a polyvinyl alcohol resin having a degree of polymerization of about greater than 0 and less than 2000, or a laminated body including the polyvinyl alcohol film, followed by wet stretching in an about 5 wt % to 10 wt % boric acid solution.
5. The method according to claim 4 , wherein the dehydration and the dry stretching are simultaneously performed.
6. The method according to claim 4 , wherein the dehydration comprises treating the polyvinyl alcohol film or the laminated body at about 100° C. to 160° C. for about 1 minute to 10 minutes.
7. The method according to claim 4 , wherein the dry stretching comprises stretching the polyvinyl alcohol film in a stretching ratio from about 2 to 6 times an initial length thereof.
8. The method according to claim 4 , wherein the wet stretching is performed in a stretching ratio from about 1 to 1.5 times an initial length of the polyvinyl alcohol with respect to the polyvinyl alcohol film after dry stretching.
9. The method according to claim 4 , wherein the polyvinyl alcohol film further comprises acid.
10. The method according to claim 9 , wherein the acid is an organic acid.
11. The method according to claim 10 , wherein the organic acid comprises a sulfonic acid of a carbon number 6-20 aromatic hydrocarbon.
12. The method according to claim 9 , wherein the acid is present in an amount of about 0.5 parts by weight to 5 parts by weight based on 100 parts by weight of the polyvinyl alcohol resin.
13. The method according to claim 4 , further comprising: immersing the polyvinyl alcohol film or the laminated body comprising the polyvinyl alcohol film in a dehydrating agent.
14. The method according to claim 4 , wherein the laminated body comprises a base film, and the polyvinyl alcohol film formed on one or both surfaces of the base film.
15. The method according to claim 14 , further comprising: removing the base film from the laminated body after wet stretching.
16. A polarizing plate comprising:
the polyene polarizer according to claim 1 ; and
an optical film or a base film, formed on one surface or both surfaces of the polyene polarizer.
17. The polarizing plate according to claim 16 , wherein the base film is formed of at least one of polyolefin, polyester, cellulose, acrylic, cycloolefin polymer(COP), polycarbonate, polyethersulfone, polysulfone, polyimide, polyimide, polyarylate, polyvinyl alcohol, polyvinyl chloride, and polyvinylidene chloride films.
18. A polarizing plate comprising:
the polyene polarizer according to claim 1 ; and
an adhesive layer formed on one or both surfaces of the polyene polarizer.
19. An optical display comprising the polarizing plate according to claim 16 .
20. An optical display comprising the polarizing plate according to claim 18 .