Permanent grayscales in bistable twisted nematic liquid-crystal displays

Abstract

Permanent grayscales in a π bistable twisted nematic-liquid-crystal display have been demonstrated. This display can be switched between the −22.5° and 157.5° twist states by a combination of a strong in-plane electric field and a vertical electric field for creating both planar anchoring breaking and an electrohydrodynamic backflow. The switching of the twist states during the Frederiks transition is sufficiently inhomogeneous such that domains of −22.5° and 157.5° twisted states can coexist permanently. The ratio of these domains can be controlled by the vertical electric field.