Photo-alignment based on azo dye-doped liquid crystals and applications

The alignment of liquid crystal (LC) molecules on a substrate is an important research/development subject, because it is a critical element for fabricating LC displays and devices. Presently, the commonly used approach for aligning LCs is based on the rubbing of polyimide (PI). The rubbed PI film is responsible for topological anisotropy of the surface of the substrate, and the related LC alignment. The topological anisotropy is typically associated with the ordered orientation of polymer molecules and/or microgrooves. Mechanical rubbing may result in static charge and dust on the surface, so non-contact alignment approaches, including photoalignment, e-beam alignment, among others are being actively studied.