Electrical modeling of liquid crystal displays-LCDs

An investigation into the complex dielectric permittivity of nematic liquid crystal (NLC) on homogeneous (or planar, molecular director axis parallel the surface of the cell) and homeotropic (molecular director axis perpendicular the surface of the cell) alignments led to the conception of special equivalent electric circuits representing different dielectric mechanisms that are present in liquid crystal displays (LCDs). In our study, NLC cells with and without polyvinyl alcohol-PVA alignment were subjected to a frequency range of 10/sup -1/ Hz to 10/sup 7/ Hz, revealing four distinct mechanisms of dielectric dispersion. In the NLC cells without PVA, the dielectric dispersion at very low frequencies (10/sup -1/ Hz10/sup 7/ Hz) dielectric dispersion was attributed mainly to the rotation of NLC molecules around their own axes. While, in the NLC cells with PVA, the dielectric dispersion at low frequencies (1 Hz