Lightness and Contrast Requirements for Legibility of Reflective Liquid-Crystal Displays : The Influence of Frame Lightness

Abstract

The purpose of this study is to investigate the required lightness and contrast for legibility of reflective liquid-crystal displays (LCDs). Thirty-seven subjects rated 65 lightness and contrast combinations displayed on the hard copy that simulate a reflective LCD, under the 500-lx illuminance condition. The results indicate that the lightness of the background should be higher than 65-70 (i.e. reflectance is 35-40%) and the contrast ratio between characters and background should be at least 5. The influence of frame lightness is not so obvious as the lightness of the background is higher than 65-70.