Influence Of Display Deveice Parameters On Perceived Brightness

Display devices have played a crucial role in people’s daily life nowadays.On top of pursuing high display quality,the influence of display device characteristics on visual health has attracted increasing attention.A combination of subjective evaluation and objective measurement was performed to research the effects of backlight luminance and color gamut on perceived brightness with varying ambient illuminance and display areas.Meanwhile,the effects of backlight luminance,ambient illuminance and display area on visual fatigue,display quality and visual comfort were explored.Thus,reference for the design of backlight luminance parameters of display devices could be provided.As the basis,the effects of backlight luminance,screen size,and image stimuli on perceived brightness were researched.Consequently,fitting curve for the most comfortable backlight luminance and the optimal luminance range on conditions of varying ambient illuminance and different screen sizes were obtained.The results showed that the optimal backlight luminance value and range ascended with the increase of ambient illumination.Moreover,the optimal comfortable backlight luminance value and range of the 55-inch display screen were both lower than those of the 75-inch display screen when the ambient illuminance remained the same.Besides,as the ambient illuminance and backlight luminance kept the same,the perceived brightness of the 55-inch display screen was higher than that of the 75-inch display screen,and the perceived brightness of image stimuli with greater color saturation was relatively higher.Founded on the research of optimal perceived brightness value and range,the effects of backlight luminance,ambient illumination and display area on visual fatigue,display quality and visual comfort were studied by means of the combination of subjective evaluation with objective physiological signal measurement.The results indicated that visual fatigue rose after watching videos with different luminance levels.Then,luminance,color saturation,contrast,and overall display quality all presented rising trend with the increase of backlight luminance that the display device could achieve.In addition,the visual comfort and watching preference were highly scored when the backlight brightness was set within the comfort brightness range,but those of score became poor as the backlight luminance was set too low or too high.Also,the visual comfort of the 55-inch display was better than that of the 75-inch display.As to ambient illuminance,the display quality at 5lx was better,while the visual comfort was lower.The equivalent backlight luminance between the display screens with different color gamut was attained by the adjusting method,and the effects of the varying color gamut on the perceived brightness was compared.Under the same backlight luminance,the perceived brightness of the display screen with larger color gamut is higher than that of the display screen with smaller color gamut.In order to obtain the same perceived brightness value,display screen with smaller color gamut required a higher backlight luminance value when displaying stimulus materials with higher saturation.Further,regarding to color evaluation,contrast evaluation and overall display quality,the larger the screen color gamut,the better.In other words,screen with greater color gamut presented better overall display performance at the same perceived brightness value.