Patent ID: 7057689

Claim:
A liquid crystal display device, comprising: a liquid crystal cell having a pair of substrates and a liquid crystal layer interposed therebetween; a pair of polarizing plates interposing the liquid crystal cell therebetween; and a phase compensation element provided between at least one of the polarizing plates and the liquid crystal cell; wherein a refractive index anisotropy value of the liquid crystal layer along a plane parallel to a surface of the liquid crystal cell is smaller in a black display than in a white display; and the phase compensation element has three principal refractive indices nx, ny and nz respectively along x, y and z axes thereof which are perpendicular to one another, and when nx and ny are the principal refractive indices along a plane parallel to a surface of the liquid crystal cell with nz being the principal refractive index along a thickness direction of the liquid crystal cell, wherein the x axis is orthogonal to an absorption axis of one of the polarizing plates closer to a viewer viewing the liquid crystal display device, and the principal refractive indices nx, ny and nz satisfy the following expressions: nz <( nx+ny )/2; and nx≠ny; wherein the liquid crystal layer includes a nematic liquid crystal material which has a negative dielectric anisotropy, where liquid crystal molecules of the nematic liquid crystal material are oriented substantially perpendicular to the substrate in an absence of an applied voltage, wherein the phase compensation element has a negative birefringence and a relationship nx>ny>nz; and wherein, for the phase compensation element, the ratio between a retardation value df·(nx−ny) of the phase compensation element along an in-plane direction thereof and a retardation value df·(nx−nz) of the phase compensation element along a thickness direction thereof is greater than or equal to 2 and less than or equal to 6.