Technique for azimuthal anchoring measurement of nematic liquid crystals using magnetic field induced deformation

摘要

The authors devised a technique for measuring the azimuthal anchoring coefficient of nematic liquid crystals. The coefficient was estimated calculating the varying ratio of magnetic coherence length to extrapolation length using light transmission to magnetic field. The paralleled control of the directors on the entrance surface, polarizer axis and magnetic field enables the transmission to sensitively reflect the anchoring. The extrapolation length was 0.48 μm for polyimide rubbed surface, 0.56 μm for rubbed poly-vinyl alcohol and 5.6 μm for photo-aligned polyimide. This technique has advantages such as insensitiveness to sample adjustment, covering wide range of anchoring and independence on the cell gap, electrodes and impurity.