Polarizing plate and optical display apparatus comprising the same
A polarizing plate and an optical display apparatus including the same are provided. A polarizing plate includes: a polarizer; and a first optically functional layer and a first protective layer sequentially stacked on a surface of the polarizer, and the optically functional layer includes a resin layer and acicular microparticles, the resin layer having a glass transition temperature (Tg) of −70° C. to −15° C. and a storage modulus of 1×10 −3 MPa to 9×10 −1 MPa at 25° C., and the acicular microparticles being oriented in an in-plane direction of the first optically functional layer, and, when a light absorption axis of the polarizer is 0°, orientation angles of longitudinal directions of the acicular microparticles with respect to the light absorption axis of the polarizer have an average value of −10° to +10° and a standard deviation of 15° or less.
1. A polarizing plate comprising:
a polarizer; and
a first optically functional layer and a first protective layer sequentially stacked on a surface of the polarizer,
wherein the first optically functional layer comprises a resin layer and acicular microparticles,
the resin layer having a glass transition temperature (Tg) of −70° C. to −15° C. and a storage modulus of 1×10 −3 MPa to 9×10 −1 MPa at 25° C., and
the acicular microparticles being oriented in an in-plane direction of the first optically functional layer, and
when a light absorption axis of the polarizer is 0°, orientation angles of longitudinal directions of the acicular microparticles with respect to the light absorption axis of the polarizer have an average value of −10° to +10° and a standard deviation of 15° or less.
2. The polarizing plate according to claim 1 , wherein the first optically functional layer comprises a contrast or brightness-enhancing layer.
3. The polarizing plate according to claim 1 , wherein the acicular microparticles have an average aspect ratio of 5 to 60.
4. The polarizing plate according to claim 1 , wherein the acicular microparticles have a length of 10 μm to 30 μm and a diameter of 0.5 μm to 2 μm.
5. The polarizing plate according to claim 1 , wherein the acicular microparticles have a higher index of refraction than the resin layer.
6. The polarizing plate according to claim 1 , wherein the acicular microparticles comprise particles formed of at least one selected from among titanium oxide, zirconium oxide, zinc oxide, calcium carbonate, boehmite, aluminum borate, calcium silicate, magnesium sulfate, magnesium sulfate hydrate, potassium titanate, glass, and a synthetic resin.
7. The polarizing plate according to claim 1 , wherein a surface of the acicular microparticles is modified.
8. The polarizing plate according to claim 7 , wherein the surface of the acicular microparticles is modified with at least one selected from among a silane coupling agent, a surfactant, and oils.
9. The polarizing plate according to claim 1 , wherein the acicular microparticles are present in an amount of 1 wt % to 30 wt % in the first optically functional layer.
10. The polarizing plate according to claim 1 , wherein the resin layer is an adhesive layer.
11. The polarizing plate according to claim 1 , wherein the resin layer is formed of a composition comprising a non-birefringent resin.
12. The polarizing plate according to claim 11 , wherein the non-birefringent resin comprises at least one selected from among a (meth)acrylate resin and a polyester resin.
13. The polarizing plate according to claim 11 , wherein the composition further comprises a curing agent.
14. The polarizing plate according to claim 1 , wherein the first optically functional layer has a thickness of 100 μm or less.
15. The polarizing plate according to claim 1 , wherein the first protective layer comprises a retardation film.
16. The polarizing plate according to claim 15 , wherein the first protective layer further comprises a functional layer comprising at least one selected from among a hard coat layer, a scattering layer, a low reflectivity layer, an ultra-low reflectivity layer, a primer layer, a fingerprint-resistant layer, an antireflection layer, and an antiglare layer.
17. The polarizing plate according to claim 1 , further comprising a second optically functional layer between the first optically functional layer and the first protective layer.
18. The polarizing plate according to claim 17 , wherein the second optically functional layer comprises a resin layer and acicular microparticles.
19. The polarizing plate according to claim 18 , wherein longitudinal directions of the acicular microparticles of the second optically functional layer form an angle of 85° to 95° with respect to the longitudinal directions of the acicular microparticles in the first optically functional layer.
20. An optical display apparatus comprising the polarizing plate according to claim 1 .