16.2: Bistable Twisted Nematic Liquid Crystals Display with Permanent Grayscales and Fast Switching

Abstract Permanent grayscales in a π bistable twisted nematic liquid crystal display have been demonstrated. This display can be switched between −22.5° and 157.5° twist states by means of a combination of strong in‐plane electric fields and vertical electric field for creating both the planar anchoring breaking and an electro‐hydrodynamic flow. The switching of the twist states during the Frederiks transition is sufficiently inhomogeneous such that domains of −22.5° twisted and 157.5° twisted states are formed. The ratio of these domains can be controlled by the vertical electric field. Fast switching of 1 ms was achieved for gray scales. These grayscales have very long lifetime.