Color image formation using polymer-dispersed cholesteric liquid crystal

A color image has been successfully formed on a stack of polymer-dispersed cholesteric (chiral nematic) liquid crystal (PDCLC) films. A combined image through the stack of PDCLC films that reflect at different wavelengths was simultaneously formed by spot heating using an infrared laser beam while controlling the electric field applied to each film. The image is written by an electric-field-assisted thermal process, in which, after partial heating, regions cooled with a field become selectively reflective and regions cooled without a field become transparent. A combined image on a two-layer stack of PDCLC films showed the feasibility of color image formation. A memory effect maintains the image for a long period without any holding techniques, and the image can easily be changed, hence, the stack of PDCLC films can be used repeatedly.