Haruo Harada

Full‐color photo‐addressable electronic paper using cholesteric liquid crystals and organic photoconductors

— Full-color photo-addressable electronic paper using cholesteric liquid crystals and organic photoconductors was developed. The electronic paper is comprised of two stacked photo-addressable elements displaying blue/green and red images, respectively. Each photo-addressable element was independently controlled by two different color-addressing lights. Furthermore, blue and green images were selectively switched by one organic photoconductor using the threshold characteristics of cholesteric liquid crystals. A highly reflective polymer-dispersed cholesteric liquid-crystal (PDCLC) layer was obtained by a new formation process based on the sol-gel transition behavior of a gelatin matrix and an agar overcoat layer. The PDCLC layer had a close-packed honeycomb-like monolayer structure with a flat surface. The A6-sized prototype had paper-like features and showed full-color bistable images instantly written with a viewer-type writing apparatus.