Determination of azimuthal anchoring energy in a twisted nematic liquid crystal.

On the basis of the torque balance equation between the twisting elastic power and the torsional anchoring energy and the Jones matrix equation of twisted nematic liquid crystals (TNLCs), an improved optical method for measuring the azimuthal anchoring strength of NLCs is proposed. In the given experimental setup, the rotation of the LC layer under fixing the transmission axis of the analyzer presents optical transmission curves to give information of the real twist angle. By rotating the analyzer with the obtained real twist angle in any rotation angle of the LC layer, cell thickness is calculated. From the obtained real twist angle and cell thickness, the azimuthal anchoring strength of nematic liquid crystals (NLCs) is easily determined.