Improvement in light out-coupling efficiency of OLED by using high fill factor parabola curve microlens arrays

•The influence of the parameters of the spherical and aspheric MLAs on the luminance efficiencywe were investigated. High fill factor parabola curve MLAs was introduced to improve the light out-coupling efficiency of OLED.•Geometric ray tracing was employed to investigate and optimize the tructure parameters of spherical and aspheric MLAs, such as the curved profile, the base shape, the fill factor, the aspect ratio (the ratio of height to diameter), and the material refractive index of the MLAs.•The experimental results are consistent with the trend of the simulation results, and show that the maximum light out-coupling efficiency of OLED improvement is 49 %.