Effect of light source, ambient illumination, character size and interline spacing on visual performance and visual fatigue with electronic paper displays

This study investigated the effects of light source, ambient illuminance, character size, and interline spacing on visual performance and visual fatigue in using commercial electronic paper displays. Regarding visual performance the results showed that display type, character size, interline spacing had significant effects on search time. Electrophoretic electronic ink display had a shorter search time than chlorestic liquid crystal display. Searching time decreased as character size and interline spacing increased. Ambient illumination, display type, character size, and interline spacing had significant effects on accuracy. Accuracy was highest for 1500 lx ambient illumination. Accuracy of electrophoretic electronic ink display was greater than chlorestic liquid crystal display. Accuracy increased as character size and interline spacing increased. Regarding visual fatigue, results showed that light source and ambient illumination had non-significant effects on change of critical flicker fusion (CFF) and subjective visual fatigue. Results could be able to provide some guidelines for consumers to choose a suitable electronic paper according to lighting condition and set appropriate character size and interline spacing.

Research highlights► Results showed that visual performance and visual fatigue did not depend on light source. ► E-paper could be used under various light sources. ► Some guidelines was provided for consumers to choose a suitable electronic paper according to the lighting condition (ambient illumination at 700 lx and greater ambient illumination such as 1500 lx may be even better for E-paper) and set character size at about 3.0 mm and retain appropriate interline spacing about 66% of character size. ► Better visual performance was shown for E-ink 401 display (Sony LIBRIe’) than Ch-LC display (Kolin i-library).