Usability Study On Mobile Phone Screen Brightness

Previous studies have shown that ambient illumination and screen brightness and contrast o fyour computer and target color and background color and its specific match can affect the user’stask performance. In this study visual search task, behavioral performance, subjective evaluationand eye fatigue indicators were used to examine the impact o f the environmental illumination oncell phone screen. The objective of this study is to investigate the effect of environmentillumination and mobile screen brightness on the performance of visual search task, and gaveoptimal values of the phone screen brightness setting parameters under different environmentillumination.In this study there were three experiments. In experiment1, when the phone screenbrightness remained unchanged, the behavioral performance, subjective evaluation and eyefatigue under different levels (0lux、100lux、500lux)of environmental illumination wereinvestigated. On the basis of the experiment1, experiment2studied the optimal values of thephone screen brightness setting parameters under different indoor environment illumination（0lux、100lux、500lux）, six screen brightness level was selected (10%,20%,40%,60%,80%.100%),the behavioral performance, subjective evaluation and eye fatigue was researchedand gave optimal values of the phone screen brightness setting parameters under different indoorenvironment illumination. On the basis of the experiment1and experiment2,experiment3studied the optimal values of the phone screen brightness setting parameters under differentoutdoor environment illumination（10klux、20klux、30klux）, six screen brightness level wasselected (10%,20%,40%,60%,80%.100%),the behavioral performance, subjective evaluationand eye fatigue was researched and gave optimal values of the phone screen brightness settingparameters under different outdoor environment illumination.The experiment results showed the following conclusions：（1） Experiment1showed that when the phone screen brightness remained the same, thevisual search performance, subjective evaluation and the degree of eye fatiguesignificantly differenced under different ambient light. According to the response accuracy under100lux significantly higher than0lux and500lux illumination.According to the subjective evaluation of indicators, eye fatigue degree of being thelowest under100lux illumination. According to the flicker fusion frequency indicator,flicker fusion frequency of the subjects under100lux ambient illumination weresignificantly higher than500lux and0lux illumination.（2） Experiment2results showed that when the ambient illumination was0lux, the bestscreen brightness degree was20%with the brightness value was11cd/m2, when theambient illumination was near100lux, the recommended screen brightness degreewas40%with the brightness value was68cd/m2and when the ambient illuminatio nwas near500lux, the recommended screen brightness degree was60%with thebrightness value was257cd/m2.（3） Experiment3results showed that when the ambient illumination was10klux, thebest screen brightness degree was60%with the brightness value was354cd/m2,when the ambient illumination was near20klux, the recommended screen brightnessdegree was80%with the brightness value was734cd/m2and when the ambientillumination was near30klux, the recommended screen brightness degree was100%with the brightness value was near1375cd/m2.