Optical laminate and optical display apparatus comprising the same
Disclosed are an optical laminate and an optical display apparatus including the same. The optical laminate includes: a polarizer; and a retardation layer stacked on a light incidence surface of the polarizer, wherein the retardation layer includes a positive C layer, the positive C layer having an in-plane retardation of 0 nm to 30 nm and an out-of-plane retardation of −50 nm to −15 nm at a wavelength of 550 nm, and the in-plane retardation of the positive C layer at a wavelength of 550 nm and an absolute value of a tilted angle of a slow axis of the positive C layer with respect to a light absorption axis of the polarizer satisfy Relation 1.
1 . An optical laminate comprising:
a polarizer; and
a retardation layer stacked on a light incidence surface of the polarizer,
wherein the retardation layer comprises a positive C layer, the positive C layer having an in-plane retardation of 0 nm to 30 nm and an out-of-plane retardation of −25 nm to −15 nm at a wavelength of 550 nm, and
the in-plane retardation of the positive C layer at a wavelength of 550 nm and an absolute value of a tilted angle of a slow axis of the positive C layer with respect to a light absorption axis of the polarizer satisfy the following Relation 1:
0°≤ Y≤a×X b ,
where X is the in-plane retardation of the positive C layer at a wavelength of 550 nm (unit: nm),
Y is the absolute value of the tilted angle of the slow axis of the positive C layer with respect to the light absorption axis of the polarizer (unit: °),
a is 13.666, and
b is −1.056, and
wherein the slow axis of the positive C layer is tilted at an angle of −14° to −1° or +1° to +14° with respect to a machine direction (MD) of the positive C layer, and the positive C layer is a stretched film and a stretched direction of the positive C layer is the machine direction (MD) of the positive C layer.
2 . The optical laminate according to claim 1 , wherein the tilted angle of the slow axis of the positive C layer with respect to the light absorption axis of the polarizer is in a range of −14° to +14°.
3 . The optical laminate according to claim 1 , wherein Y in Relation 1 is in a range of 0° to 14.5°.
4 . The optical laminate according to claim 1 , wherein the retardation layer is the positive C layer alone.
5 . The optical laminate according to claim 1 , wherein the positive C layer comprises a stretched non-liquid crystalline film.
6 . The optical laminate according to claim 5 , wherein the positive C layer comprises a stretched film comprising at least one resin selected from among a cellulose ester based resin, a polyester based resin, a cyclic polyolefin based resin, a polycarbonate based resin, a polyethersulfone based resin, a polysulfone based resin, a polyamide based resin, a polyimide based resin, a polyolefin based resin, a polyarylate based resin, a polyvinyl alcohol based resin, a polyvinyl chloride based resin, a polyvinylidene chloride based resin, and an acrylic based resin.
7 . The optical laminate according to claim 1 , wherein the positive C layer is stacked on the polarizer via a bonding layer.
8 . The optical laminate according to claim 1 , further comprising a protective layer stacked on a light exit surface of the polarizer.
9 . The optical laminate according to claim 8 , wherein a tilted angle of a slow axis of the protective layer with respect to the slow axis of the positive C layer is in a range of −14° to +14°.
10 . The optical laminate according to claim 8 , wherein the protective layer has an in-plane retardation of 3,000 nm or more at a wavelength of 550 nm.
11 . An optical display apparatus comprising the optical laminate according to claim 1 .