Patent ID: 7084939

Claim:
A normally white supertwist nematic liquid crystal display comprising: a reflector, a layer of chiral nematic liquid crystal having a front aligning surface facing a light source and a rear aligning surface facing the reflector, said nematic liquid crystal having an optical retardation (Δnd) of the layer and a distribution of directors, wherein said chiral nematic liquid crystal has a twist angle (Φ) between an alignment direction of a director at the front aligning surface and an alignment direction of a director at the rear aligning surface; and a front polarizer disposed between the layer of the chiral nematic liquid crystal and the light source, said front polarizer has a transmission axis forming an angle (α) with the alignment direction of the director at the front aligning surface of the chiral nematic liquid crystal layer; wherein the optical retardation (Δnd) and the angle (α) are defined by the following formulas: α(Φ)=sign(Φ)·(47.0−0.4936 |Φ|+2.6786×10 −3 ·Φ 2 )±5, deg, and Δ nd (Φ)=−11.674+0.1915·|Φ|−9.8393×10 −4 ·Φ 2 +1.6667×10 −6 ·|Φ| 3 ±0.05, μm; and wherein the front polarizer is made out of an optically anisotropic dichroic thin crystal film material which comprises aromatic rings and has an intermolecular spacing of 3.4±0.3 Å in the direction of one of optical axes.