It is experiemntally demonstrated that selecting a proper wave length of the incident light is required to aviod the Mauguin Minimum condition in which the actual twist angle cannot be estimated by optical measurement. The all of the optical component such as the glass substrates, indium tin oxide electrode films, alignment films and liquid crystals itself play an important role in the optical polarization state of the outgoing light, therefore, we re-examined the measurement method for the evaluation of the anchoring strength and proposed a modified method by using multicolor laser.
