A bistable liquid crystal cell with splay and π twist stable states is obtained by doping a chiral additive in a splay cell filled with dual frequency liquid crystals. The switching between the two states is achieved by using a sequential waveform of low and high frequencies. The switching mechanisms are proposed by using the backflow effect together with the anisotropic properties of dual frequency liquid crystals. As a result, the two stable states have the superior memory characteristics due to the topological inequivalence.

We have proposed a method for detecting and classifying the mura phenomena. The related theory and experiments of how to measure the mura phenomena are discussed in this paper. By using the flicker measurement with related brightness evaluation, we can not only classify the electrical and non-electrical mura but also setup a quantitative judgment criterion for the mura grade. It benefits us to improve the image quality and to quickly determine the root causes of the mura phenomena.