Lesiuk A. Orientation phenomena in a liquid crystal cell with spatially modulated surface and controlled easy axis

The thesis is dedicated to investigation of equilibrium two-dimensional configurations of the director field of nematic liquid crystal (NLC) in a cell with one periodic spatially modulated surface in presence and absence of the disclinationlines in the bulk. The dependence of the position of the disclination lines on the thickness of the cell, the period and the depth of the relief surface modulation was established. The influence of an electric field on the orientational instability of the NLC in a planar cell with tunable by the electric field boundary conditions was investigated. The reorientation of NLC director with negative and positive dielectric anisotropy in an electric field in a homotropic cell with controlled by the electric field boundary conditions was investigated. The dependence of the threshold of the orientational instability of the NLC on the parameter of the influence of the electric field on the easy axis of the director orientation on one of the cell surfaces was established. The transmission of monochromatic linearly polarized light through the cell of the NLC with boundary conditions controlled by an electric field was studied.