Patent ID: 8842243
Filing Date: 2014-09-23
Classification: G02B,G02F

Abstract:
1. An IPS or FFS-mode liquid-crystal display device comprising: a first polarizing film, an optical compensatory film comprising a first retardation region and a second retardation region adjacent to the first retardation region, a first substrate, a liquid-crystal layer comprising a nematic liquid-crystal material, and a second substrate, a second polarizing film on the more outer side of the second substrate in that order, wherein: liquid-crystal molecules of the nematic liquid-crystal material are aligned parallel to the surfaces of the pair of substrates at the black state, a slow axis of the first retardation region is parallel to a slow axis of the second retardation region, an absorption axis of the first polarizing film and an absorption axis of the second polarizing film are disposed orthogonally to each other, a slow axis of the liquid-crystal layer is parallel to the absorption axis of the second polarizing film, the absorption axis of the first polarizing film is parallel to the slow axis of the first retardation region and the slow axis of the second retardation region, retardation in-plane at a wavelength of 550 nm, Re(550) of the second retardation region is equal to or less than 20 nm, and retardation along the thickness-direction at a wavelength of 550 nm, Rth(550) of the second retardation region is from 20 nm to 120 nm, the first retardation region comprises a retardation layer containing a vertically-aligned discotic liquid-crystal compound, and Re thereof at a wavelength of 450 nm, 550 nm and 650 nm, Re(450), Re(550) and Re(650) satisfy Re(450)/Re(550) of from 1 to 1.13 and Re(650)/Re(550) of from 0.94 to 1, where retardation in-plane Re and retardation along the thickness-direction Rth are defined as Re=(nx−ny)×d, and Rth={(nx+ny)/2−nz}×d, in which nx and ny each are the in-plane refractive index (nx≧ny), nz is the thickness-direction refractive index, and d is the thickness of the film.