Optical laminate including reddening-resistant layer
An optical laminate, including: a polarizing layer; and a porous layer formed on at least one side of the polarizing layer, wherein the polarizing layer includes zinc component, and wherein an absolute value of a change in an amount of color coordinate a* of CIE L*a*b* according to Equation 1 is 2 or less: Δ a*=a* a −a* i [Equation 1] wherein Δa* is the change in the amount of the color coordinate a*, a* a is a color coordinate a* of the optical laminate after maintaining the optical laminate at 105° C. for 250 hours under a state where both top and bottom surfaces of the optical laminate come in contact with glass substrates, and a* i is a color coordinate a* of the optical laminate before maintaining the optical laminate at 105° C. for 250 hours.
1. An optical laminate, comprising:
a polarizing layer; and
a porous layer formed on at least one side of the polarizing layer,
wherein the polarizing layer comprises zinc component, and
wherein an absolute value of a change in an amount of color coordinate a* of CIE L*a*b* according to Equation 1 is 2 or less:
Δ a*=a* a −a* i [Equation 1]
wherein Δa* is the change in the amount of the color coordinate a*, a* a is a color coordinate a* of the optical laminate after maintaining the optical laminate at 105° C. for 250 hours under a state where both top and bottom surfaces of the optical laminate come in contact with glass substrates, and a* i is a color coordinate a* of the optical laminate before maintaining the optical laminate at 105° C. for 250 hours.
2. The optical laminate according to claim 1 , wherein the polarizing layer is an iodine-based polarizing layer.
3. The optical laminate according to claim 1 , wherein the polarizing layer satisfies Equation 3:
0.70 to 0.97=1/(1+0.025 d/R ) [Equation 3]
wherein d is a thickness (μm) of the polarizing layer, and R is a ratio (K/Zn) of a weight ratio (K, unit:weight %) of potassium component in the polarizing layer with respect to a weight ratio (Zn, unit:weight %) of zinc component in the polarizing layer.
4. The optical laminate according to claim 1 , wherein the porous layer satisfies Equation 4:
H L ≤0.9× H P [Equation 4]
wherein H L is a thermal diffusivity of a laminate of a polymer film and the porous layer formed on one side of the polymer film, and H P is the thermal diffusivity of the polymer film.
5. The optical laminate according to claim 1 , wherein the porous layer comprises a surface having a surface area ratio of 0.02 or more as measured by an atomic force microscope.
6. The optical laminate according to claim 1 , wherein the porous layer has reflectance of 2% or more with respect to light having a wavelength of 800 nm to 1300 nm.
7. The optical laminate according to claim 1 , wherein the porous layer exhibits at least one peak within a scattering vector range of 0.06 to 0.209 nm −1 in a log value graph of scattering intensity of small angle X-ray scattering.
8. The optical laminate according to claim 1 , wherein an A value satisfying Equation 6 of the porous layer is 1.1 to 1.5, a B value satisfying Equation 6 of the porous layer is from 0.0001 to 0.01 and a C value satisfying Equation 6 of the porous layer is from 0.000001 to 0.001:
n
(
λ
)
=
A
+
B
λ
2
+
C
λ
4
[
Equation
6
]
wherein, n (λ) is the refractive index of the porous layer at a wavelength of λ, and λ is any one wavelength in a range of 300 to 1800 nm.
9. The optical laminate according to claim 1 , wherein the porous layer comprises a binder and hollow particles.
10. The optical laminate according to claim 9 , wherein the binder comprises a polymer derived from a polyfunctional acrylate having 2 to 10 polymerizable functional groups.
11. The optical laminate according to claim 9 , wherein the hollow particles have a D10 particle diameter in a range from 25 to 50 nm, a D50 particle diameter in a range from 50 to 95 nm and a D90 particle diameter in a range from 100 nm to 200 nm in a weight cumulative curve of particle size distribution.
12. The optical laminate according to claim 1 , wherein the porous layer does not comprise solid particles.
13. The optical laminate according to claim 1 , wherein the porous layer has a thickness of 200 nm or more.
14. The optical laminate according to claim 1 , wherein the porous layer does not form a surface of an outermost layer in the optical laminate.
15. The optical laminate according to claim 1 , further comprising an additional layer selected from the group consisting of a protective film, a pressure-sensitive adhesive layer, an adhesive layer, a hard coating layer, an antireflection layer, a retardation layer and a brightness enhancement layer,
wherein the porous layer is disposed between the additional layer and the polarizing layer.
16. The optical laminate according to claim 1 , wherein a distance between the porous layer and the polarizing layer is 90 μm or less.