| Title |
Effect of Luminance Contrast Ratio of Character on Readability and Visual Fatigue during Long-term Reading Using Tablet PC in Low Luminance Environment |
| Authors |
Yu, Hanui ; Akita, Takeshi |
| DOI |
https://doi.org/10.5659/JAIK_SC.2019.35.5.191 |
| Keywords |
Tablet PC ; Visual Fatigue ; Readability ; Luminance Contrast Ratio of Character ; Low-luminance Environment |
| Abstract |
This study examines the effect of luminance contrast ratio of character on readability and visual fatigue during an hour-long reading session
while using a tablet PC in ambient environments having low luminance limited to 25 cd/㎡. Experiments were conducted with four patterns
of the tablet’s luminance contrast ratio of characters, namely 1:2.5, 1:4.5, 1:6.5, and 1:8.5, in low ambient luminance of 9 cd/㎡ and 25 cd/
㎡. The obtained results show that the characters can be easily read at the luminance contrast ratio of character of 1:8.5 under surface
luminance of 25 cd/㎡. Visual fatigue was evaluated through a subjective survey of symptoms. Physical, psychological, and visual fatigue
were observed at a surface luminance of 9 cd/㎡, whereas solely visual fatigue was felt at a surface luminance of 25 cd/㎡. By assessing
the physical fatigue using the value, it has been found that smaller the luminance contrast ratio of character, greater is the CFF variation
rate. Furthermore, readability is poor and visual fatigue can be observed when the surface luminance is lower than the ambient luminance.
However, readability can be improved by increasing the luminance contrast ratio of character to a value of 1:8.5. Thus, in low luminance
environments, luminance contrast ratio of characters can affect readability and fatigue. Consider providing the full form of “CFF” so that the
acronym can be used unambiguously throughout the manuscript. |