Control of molecular orientation in liq. crystals - by applying electric field at varying frequencies

摘要

Control of the collective orientation of the molecules of a liquid crystal under the effect of an electric field, where the liquid crystal exhibits dielectric anisotropy i.e. having a dielectric constant parallel to the major axis of a liquid crystal molecule which differs from that parallel to the minor axis of the molecule, the anisotropy being characterised in magnitude and sign by (a) selecting a liq. crystal for which two frequencies (F1, F2) exist for which the dielectric anisotropies have opposite signs, (b) applying a first electric field of frequency (f1) to the selected liquid crystal to cause one of the two axes of each molecules to be rotated in the direction of the field (c) thereafter applying a second electric field of frequency (F2) in the same direction as the first field which causes the other axis to turn in the direction of the field. Enables the refractive index to be controlled by controlling the orientation of the molecules of the liquid crystal, for use in optical systems, e.g. colour television, photo-composition etc.