Liquid crystal display device
Provided is a liquid crystal display device comprising: a light source having a wide color reproduction range; a liquid crystal panel; and a polarizing plate arranged on the visible side of the liquid crystal panel, wherein the polarizing plate comprises a polarizer and a polarizer protecting film; the polarizer protecting film comprises a polyester base film having an in-plane phase difference of 8,000 nm or higher at a wavelength of 550 nm and a primer layer formed on at least one surface of the polyester base film; and a coating layer having a lower refractive index than the primer layer is additionally formed on a surface of the primer layer.
1. A liquid crystal display device comprising: a high color gamut light source; a liquid crystal panel; and a polarizing plate disposed at a viewer side of the liquid crystal panel,
wherein the polarizing plate comprises a polarizer and a polarizer protective film,
the polarizer protective film comprising: a polyester base film having an in-plane retardation of 8,000 nm or more at a wavelength of 550 nm, as represented by Equation 1; a primer layer formed on at least one surface of the polyester base film; and a coating layer formed on one surface of the primer layer and having a lower refractive index than the primer layer:
Re =( nx−ny )× d <Equation 1>
where nx and ny are refractive indices in the slow axis and fast axis directions of the polyester base film at a wavelength of 550 nm, respectively, and d is a thickness of the polyester base film (unit: nm),
the polyester base film has an out-plane retardation of 15,000 nm or less at a wavelength of 550 nm, as represented by Equation 2:
Rth =(( nx+ny )/2− nz )× d <Equation 2>
where nx, ny and nz are the refractive indices of the polyester base film in the slow axis, fast axis, and thickness directions thereof at a wavelength of about 550 nm, respectively, and d is the thickness of the polyester base film (unit: nm), and
the polyester base film has a degree of biaxiality of 1.8 or less at a wavelength of 550 nm, as represented by Equation 3:
NZ =( nx−nz )/( nx−ny ) <Equation 3>
where nx, ny and nz are the refractive indices of the polyester base film in the slow axis, fast axis, and thickness directions thereof at a wavelength of about 550 nm, respectively.
2. The liquid crystal display device according to claim 1 , wherein the high color gamut light source has a color gamut of 95% or more by the National Television System Committee (NTSC) in a CIE 1031 x, y, chromaticity diagram.
3. The liquid crystal display device according to claim 1 , wherein the high color gamut light source comprises at least one of a quantum dot light source and a metal fluoride-based red phosphor-containing light source.
4. The liquid crystal display device according to claim 3 , wherein the metal fluoride-based red phosphor-containing light source comprises KSF (K 2 SiF 6 :Mn 4+ ) phosphors or KTF (K 2 TiF 6 :Mn 4+ ) phosphors.
5. The liquid crystal display device according to claim 1 , wherein the coating layer is thicker than the primer layer.
6. The liquid crystal display device according to claim 1 , wherein the coating layer, the primer layer, and the polyester base film satisfy Formulas 4 and 5:
n 1< n 2< n 3 <Formula 4>
where n1 is a refractive index of the coating layer, n2 is a refractive index of the primer layer, and n3 is a refractive index of the polyester base film;
T 2< T 1< T 3 <Formula 5>
where T1 is a thickness of the coating layer, T2 is a thickness of the primer layer, and T3 is a thickness of the polyester base film.
7. The liquid crystal display device according to claim 1 , wherein the coating layer has a refractive index of 1.0 to 1.6 and the coating layer has a thickness of 1.0 μm to 10.0 μm.
8. The liquid crystal display device according to claim 1 , wherein the primer layer has a refractive index of 1.0 to 1.6 and a thickness of 1 nm to 200 nm.
9. The liquid crystal display device according to claim 1 , wherein the polyester base film has a refractive index of 1.3 to 1.7.
10. The liquid crystal display device according to claim 1 , wherein the polyester base film is formed of a composition comprising at least one of polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, and polybutylene naphthalate.
11. The liquid crystal display device according to claim 1 , wherein a functional layer is further formed on one surface of the coating layer.
12. The liquid crystal display device according to claim 11 , wherein the functional layer has at least one function selected from among anti-reflection, low reflection, hardcoating, anti-glare, anti-fingerprint, anti-contamination, diffusion and refraction functions.