Optical laminate
The present disclosure relates to an optical laminate or a reddening-resistant layer. The present disclosure can provide an optical laminate that does not cause a so-called reddening phenomenon even when driven or maintained under extremely harsh conditions (e.g., very high temperature conditions), or a reddening-resistant layer applied thereto.
1. An optical laminate, comprising:
a polarizing layer comprising zinc component; and
a reddening-resistant layer formed on at least one side of the polarizing layer,
wherein the reddening-resistant layer is a void-containing layer or a laminate comprising the void-containing layer and the void-containing layer has a thickness of 400 nm or more,
wherein the reddening-resistant layer has an average reflectance in a wavelength region of 800 to 1300 of 2% or more,
wherein the void-containing layer comprises a binder and hollow particles, and
wherein the hollow particles have a D10 particle diameter of 25 to 50 nm. a D50 particle diameter of 50 to 95 nm and a D90 particle diameter of 100 nm to 200 nm in a weight cumulative curve of particle size distribution.
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 reddening-resistant 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 reddening-resistant 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 reddening-resistant 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 reddening-resistant 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.
7. The optical laminate according to claim 1 , wherein an A value satisfying Equation 6 of the reddening-resistant layer is 1.5 or less, a B value satisfying Equation 6 of the reddening-resistant layer is from 0 to 0.01 and a C value satisfying Equation 6 of the reddening-resistant layer is from 0 to 0.001:
n
(
λ
)
=
A
+
B
λ
2
+
C
λ
4
[
Equation
6
]
wherein n(λ) is the refractive index of the reddening-resistant layer at a wavelength of λ, and λ is any one wavelength in a range of 300 to 1800 nm.
8. The optical laminate according to claim 1 , wherein the binder comprises a polymer derived from a polyfunctional acrylate having 2 to 10 polymerizable functional groups.
9. The optical laminate according to claim 1 , wherein the void-containing layer does not comprise solid particles.
10. The optical laminate according to claim 1 , wherein the reddening-resistant layer does not form a surface of an outermost layer of the optical laminate.
11. The optical laminate according to claim 1 , further comprising an additional layer, wherein the reddening-resistant layer is disposed between the additional layer and the polarizing layer.
12. The optical laminate according to claim 1 , wherein the distance between the reddening-resistant layer and the polarizing layer 90 μm or less.