Fast-Switching Stratified Polymer-Stabilized Liquid Crystal for Flexible Display Applications

A new liquid-crystal device for flexible display applications was developed using twofold polymerization process. The cell was fabricated from a homogeneous mixture of a liquid crystal and a polymerforming material. Caused by the spatially nonuniform rate of polymerization and wetting properties, largescale anisotropic phase separation of the liquid-crystal blend and the polymer precursor leads to a stratified structure of a solidified film of polymer on the UVilluminated substrate and a nematic liquid-crystal film with an in-situ reduction of the cell gap on the alignment layer. A second step of UV exposure from the other direction allows the residual monomer in the liquid crystal to polymerize, forming a typical polymer networkstabilized liquid crystal underneath the hard polymer coating. In comparison with the Paintable liquid-crystal display technology or the pixel-isolated liquid-crystal mode, such a stratified polymer-stabilized liquid crystal requires only a very simple processing procedure for manufacturing and is demonstrated to be fast-switching, exhibiting a response time of the order of 1 ms. This innovation, taking the advantages of a phase-separated composite film as well as a polymer-stabilized liquid crystal, can be applied to flexible display technology with a reasonable mechanical stability.