In-plane switching liquid crystal display
There is provided an integrated wide viewing film including: a first film having an optical axis located in-plan; and a second film having an optical axis located in a thickness direction thereof, and inclined at a predetermined angle in an in-plane direction. The IPS-LCD employing the integrated wide viewing film can be significantly improved in a contrast ratio in a diagonal direction.
1. An in-plane switching liquid crystal display comprising:
a liquid crystal panel including an upper substrate, a lower substrate and a liquid crystal cell filled with a liquid crystal having a positive dielectric anisotropy;
first and second polarized plates disposed on both sides of the liquid crystal panel, respectively; and
an integrated wide viewing film including:
a +A-film satisfying n x >n y =n z and having an optical axis located in-plan; and
a +C-film satisfying n x =n y <n z and having an optical axis located in a thickness direction thereof,
wherein the optical axis of the +C-film is, for the purpose of optimization, inclined at an angle not less than −5° and not to exceed +5°, with respect to a vertical direction in an in-plane direction,
wherein the liquid crystal in the liquid crystal cell has an optical axis located in-plane parallel to the polarized plates, respectively, and
wherein the first and second polarized plates have absorption axes perpendicular to each other.
2. The in-plane switching liquid crystal display of claim 1 , wherein the +A-film has an in-plane retardation of 50 nm to 150 nm at a wavelength of 550 nm, and
the +C-film has a thickness retardation of 50 nm to 250 nm at a wavelength of 550 nm.
3. The in-plane switching liquid crystal display of claim 1 , wherein the +A film has the optical axis disposed perpendicular to an absorption axis of the second polarized plate.
4. The in-plane switching liquid crystal display of claim 3 , wherein the liquid crystal cell has a splay orientation of liquid crystal.
5. The in-plane switching liquid crystal display of claim 1 , wherein the +A film has the optical axis disposed parallel to an absorption axis of the second polarized plate.
6. The in-plane switching liquid crystal display of claim 5 , wherein the liquid crystal cell has a homogeneous orientation of liquid crystal.
7. The in-plane switching liquid crystal display of claim 1 , wherein the +A-film is a polymer film and the +C-film is a liquid crystal film.
8. The in-plane switching liquid crystal display of claim 1 , wherein the liquid crystal cell has a retardation of 300 nm to 400 nm at a wavelength of 550 nm.
9. The in-plane switching liquid crystal display of claim 1 , wherein each of the first and second polarized plates use an isotropic film as a protective film.
10. The in-plane switching liquid crystal display of claim 9 , wherein the isotropic film is a cyclo-olefin polymer (COP) or a Zero TAC film having no retardation.
11. The in-plane switching liquid crystal display of claim 1 , wherein the integrated wide viewing film is directly stacked on the polarized film of the second polarized plate to serve as a protective film.