Liquid crystal display device having red, green and blue filters in which the liquid crystal layer thickness for the red filter portion is equal to the green filter portion but greater than the blue filter portion
View Patent ↗First and second polarization plates are disposed on both sides of a liquid crystal panel in which thicknesses of a liquid crystal layer are set up depending on colors of color filters. Then, a first retardation film is disposed between the liquid crystal panel and the first polarization film, and a second retardation film is disposed between the liquid crystal panel and the second polarization film. Assuming that a maximum value of a refractive index in an in-plane direction out of principal indices of refraction is Nx, that a refractive index in an orthogonal direction to the direction of the refractive index which has the value of Nx is Ny, and that a thickness is d, the first and second retardation films are set to satisfy a difference in values of (Nx−Ny)×d equal to or less than 10 nm.
1. A liquid crystal display device comprising:
a liquid crystal panel in which thicknesses of a liquid crystal layer are set up depending on colors of color filters;
first and second polarization plates disposed so as to interpose the liquid crystal panel;
a first retardation film disposed between the liquid crystal panel and the first polarization plate; and
a second retardation film disposed between the liquid crystal panel and the second polarization plate;
wherein, assuming that a maximum value of a refractive index in an in-plane direction out of principal indices of refraction is Nx, that a refractive index in an orthogonal direction to the direction of the refractive index which has the value of Nx is Ny, and that a thickness is d, the first and second retardation films are set to satisfy a difference in values of (Nx−Ny)×d equal to or less than 10 nm,
absorption axes of the first and second polarization plates are disposed orthogonally to each other,
a slow axis of the first retardation film is disposed orthogonally to the absorption axis of the first polarization plate,
a slow axis of the second retardation film is disposed orthogonally to the absorption axis of the second polarization plate,
the liquid crystal panel comprises a pair of substrates, and liquid crystal having negative dielectric constant anisotropy which is sealed between the substrates,
wherein three types of color filters in red, green, and blue are provided as the color filters,
wherein a thickness of a liquid crystal layer at a portion where the red color filter is formed is greater than a thickness of the liquid crystal layer at a portion where the blue color filter is formed, and
wherein the thickness of the liquid crystal layer at the portion where the red color filter is formed is equal to a thickness of the liquid crystal layer at a portion where the green color filter is formed.
2. The liquid crystal display device according to claim 1 ,
wherein a thin film transistor and a picture element electrode connected to the thin film transistor are formed for each picture element on one of the pair of substrates, and
a common electrode opposed to the picture element electrode is formed on the other substrate.
3. The liquid crystal display device according to claim 1 ,
wherein, assuming that a refractive index in a thickness direction is Nz, the first and second retardation films respectively satisfy a relation of Nx>Ny=Nz.
4. The liquid crystal display device according to claim 3 ,
wherein a third retardation film satisfying a relation of Nx=Ny>Nz is disposed between the liquid crystal panel and the first retardation film.
5. The liquid crystal display device according to claim 3 ,
wherein a third retardation film satisfying a relation of Nx=Ny>Nz is disposed between the liquid crystal panel and the second retardation film.
6. The liquid crystal display device according to claim 1 ,
wherein at least any one of the first and second retardation films is an assembly of a plurality of layers having refractive index anisotropies.