Viewer-side polarizing plate for liquid crystal display device, and liquid crystal display device comprising same
Provided are a viewer-side polarizing plate for a liquid crystal display device, and a liquid crystal display device comprising the same, the polarizing plate comprising a polarizer and a protective film formed on a light exit surface of the polarizer, wherein the protective film includes a first primer layer, a protective film substrate, a second primer layer, and a coating layer, which are sequentially laminated on the polarizer, a first protective film satisfies a relation of Equation 1, and the protective film substrate has an in-plane phase difference of 500 nm or less at a wavelength of 550 nm in Equation 2.
1. A viewer-side polarizing plate for liquid crystal display devices, comprising: a polarizer; and a first protective film formed on a light exit surface of the polarizer,
wherein the first protective film comprises a first primer layer, a protective film matrix, a second primer layer, and a coating layer sequentially stacked on the polarizer,
the first protective film satisfying Relation 1:
( nc+ns )/2−0.025≤ np 2≤( nc+ns )/2+0.025, <Relation 1>
where nc indicates a refractive index of the coating layer, ns indicates a refractive index of the protective film matrix, and np 2 indicates a refractive index of the second primer layer,
the protective film matrix having an in-plane retardation of 500 nm or less at a wavelength of 550 nm, as represented by Equation 2:
Re=( nx−ny )× d, <Equation 2>
where nx and ny are refractive indices of the protective film matrix in the slow-axis and fast-axis directions thereof at a wavelength of 550 nm, respectively, and d is a thickness of the protective film matrix (unit: nm), and
wherein, when np 1 indicates a refractive index of the first primer layer, np 1 , np 2 , nx, and ny of the first protective film satisfy Relation 5 or 6:
np 2≤ np 1≤ ny≤nx; <Relation 5>
np 2≤ np 1≤ nx≤ny. <Relation 6>
2. The viewer-side polarizing plate for liquid crystal display devices according to claim 1 , wherein the protective film matrix is a polyester film matrix.
3. The viewer-side polarizing plate for liquid crystal display devices according to claim 2 , wherein the polyester comprises at least one of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate.
4. The viewer-side polarizing plate for liquid crystal display devices according to claim 1 , wherein at least one of the first primer layer and the second primer layer has a refractive index of greater than 1.5.
5. The viewer-side polarizing plate for liquid crystal display devices according to claim 1 , wherein each of the first primer layer and the second primer layer has a refractive index of greater than 1.5.
6. The viewer-side polarizing plate for liquid crystal display devices according to claim 1 , wherein each of the first primer layer and the second primer layer has a thickness of 60 nm to 120 nm.
7. The viewer-side polarizing plate for liquid crystal display devices according to claim 1 , wherein the first protective film has a haze of 1.5% or less.
8. The viewer-side polarizing plate for liquid crystal display devices according to claim 7 , wherein the haze of the first protective film is 1.2% or less.
9. The viewer-side polarizing plate for liquid crystal display devices according to claim 7 , wherein the haze of the first protective film is 0.7% or less.
10. The viewer-side polarizing plate for liquid crystal display devices according to claim 1 , wherein the refractive index of the coating layer is 1.52 to 1.60.
11. The viewer-side polarizing plate for liquid crystal display devices according to claim 1 , wherein the coating layer has a thickness of 1 μm to 20 μm.
12. The viewer-side polarizing plate for liquid crystal display devices according to claim 1 , further comprising: a second protective film formed on a light incidence surface of the polarizer.
13. A liquid crystal display device comprising a liquid crystal panel and a polarizing plate disposed at a viewer side of the liquid crystal panel,
wherein the polarizing plate comprises the viewer-side polarizing plate for liquid crystal display devices according to claim 1 .
14. A viewer-side polarizing plate for liquid crystal display devices, comprising: a polarizer; and a first protective film formed on a light exit surface of the polarizer,
wherein the first protective film comprises a first primer layer, a protective film matrix, a second primer layer, and a coating layer sequentially stacked on the polarizer,
the first protective film satisfying Relation 1:
( nc+ns )/2−0.025≤ np 2≤( nc+ns )/2+0.025, <Relation 1>
where nc indicates a refractive index of the coating layer, ns indicates a refractive index of the protective film matrix, and np 2 indicates a refractive index of the second primer layer,
the protective film matrix having an in-plane retardation of 500 nm or less at a wavelength of 550 nm, as represented by Equation 2:
Re=( nx−ny )× d, <Equation 2>
where nx and ny are refractive indices of the protective film matrix in the slow-axis and fast-axis directions thereof at a wavelength of 550 nm, respectively, and d is a thickness of the protective film matrix (unit: nm), and
wherein the first protective film further comprises: a low refractivity layer formed on an upper surface of the coating layer and having a lower refractive index than the coating layer.
15. The viewer-side polarizing plate for liquid crystal display devices according to claim 14 , wherein the first protective film has a minimum reflectivity of 0.5% or less.
16. A viewer-side polarizing plate for liquid crystal display devices, comprising: a polarizer; and a first protective film formed on a light exit surface of the polarizer,
wherein the first protective film comprises a first primer layer, a protective film matrix, a second primer layer, and a coating layer sequentially stacked on the polarizer,
the first protective film satisfying Relation 1:
( nc+ns )/2−0.025≤ np 2≤( nc+ns )/2+0.025, <Relation 1>
where nc indicates a refractive index of the coating layer, ns indicates a refractive index of the protective film matrix, and np 2 indicates a refractive index of the second primer layer,
the protective film matrix having an in-plane retardation of 500 nm or less at a wavelength of 550 nm, as represented by Equation 2:
Re=( nx−ny )× d, <Equation 2>
where nx and ny are refractive indices of the protective film matrix in the slow-axis and fast-axis directions thereof at a wavelength of 550 nm, respectively, and d is a thickness of the protective film matrix (unit: nm), and
wherein the first protective film further comprises: a high refractivity layer and a low refractivity layer sequentially formed on an upper surface of the coating layer,
the low refractivity layer having a lower refractive index than the high refractivity layer.
17. The viewer-side polarizing plate for liquid crystal display devices according to claim 16 , wherein the first protective film has a minimum reflectivity of 0.5% or less.