Influence of ambient temperature on OLED lifetime and uniformity based on modified equivalent lifetime detection

摘要

The ambient temperature can affect the OLED heat dissipation and aggravate the luminance degradation. Based on temperature-related equivalent lifetime detection, a luminance compensation algorithm without internal or external sensing circuits is proposed and the influence of ambient temperature on lifetime and display uniformity is studied. First, the parameters of luminance degradation curves at any ambient temperature are calculated according to the relationship between accelerate degradation factor n and ambient temperature T, which is determined by the measured luminance degradation curves at ambient temperature 25 degrees C, 45 degrees C, and 80 degrees C. Second, luminance compensation is carried out by increasing drive current according to the estimated luminance degradation influenced by temperature. Furthermore, compensation iterations m, compensation goal value L-goal, and compensation origin value L-origin are optimized to obtain a better lifetime extension at different ambient temperature. The simulated and experimental results indicate that the lifetime extensions considering the influence of ambient temperature at 0 degrees C, 25 degrees C, 45 degrees C, 60 degrees C, and 80 degrees C are 29.7%, 28.1%, 18.7%, 18.9%, and 11.6%. Meanwhile, after displaying an image of the International Electrotechnical Commission (IEC) 62087 for 90 hours, the luminance uniformity of OLED increase to 96.0%, 94.0%, 97.2%, 97.2%, and 98.6%, which is a significant improvement compared with it of regardless the influence of the ambient temperature.