E-Paper Displays

6The Zenithal Bistable Display: A Grating Aligned Bistable Nematic Liquid Crystal Device

Guy P. Bryan‐Brown¹ and J. Cliff Jones²

¹ New Vision Displays Inc., Malvern, Worcestershire, UK

² School of Physics and Astronomy, University of Leeds, Leeds, UK

6.1 Introduction

Paper has several attributes that any replacement technology must target. Its properties include having high reflectance (>70%), sufficient contrast (>8 : 1), light weight, and flexibility. By its nature, paper is inherently high resolution, well above the limit of human vision. Although most often used for black and white text images, it can display full color images of photographic quality. Once written on, the image is retained for years. Paper is usually considered to be low cost, though its economic and environmental costs are not as clear when compared to an electronic display because of its write‐once‐read‐many nature.

It is the ability to update the image that drives electronic paper requirements. The update will be occasional for many applications, although regular updates are often required. Electronic paper technology is concerned with developing displays that add updateability to as many of these attributes of paper as possible. Of these paper‐like qualities, it is essential to display the desired image without continuous electrical power. This necessitates electronic paper to be a bistable, reflective display. Being a reflective display limits the image quality possible with any electronic paper, and ...