Reflective Color Display Using Polymer-Dispersed Cholesteric Liquid Crystal

A reflective color display with a passive matrix has been successfully obtained using polymer-dispersed cholesteric (chiral nematic) liquid crystal (PDCLC). The PDCLC has two memory states: a selectively reflective state and a transparent one. These states are maintained for a long period without any holding techniques. These states can be changed electrically: a high-frequency electric field induces the reflective state and a low-frequency field recovers the transparent state due to the Carr-Helfrich instability. A driving scheme using dual-frequency fields was applied to a passive matrix of 8×8 to rewrite images on the matrix. This technique will lead to reflective-color display devices with high information content.