Active compensation technique for the thin-film transistor variations and OLED aging of mobile device displays

OLED is becoming the main stream display for mobile devices. The process variations of thin-film transistors (TFT) and the aging degradation of OLED devices severely impact the display quality and the user experience on mobile devices throughout lifetime. In this paper, we quantitatively study the nonuniformity of OLED display panels incurred by the TFT variations and OLED cell aging effect. Furthermore, we develop a pixel level sensing circuit that detects and quantifies the nonuniformity condition and corresponding compensating technique. This proposed technique can be actively invoked based on various conditions with flexible configuration and minimal extra overhead, which is suitable to be integrated with mobile displays. The proposed technique´s performance is simulated with different display contents. Experiments show that: for the proposed sensing circuit, the error rate for TFT process variation evaluation is only 4.7%~7.9%, and 0.29%~7.6% for OLED aging degradation. And for typical mobile display content, the compensation rate reaches 94.04%~100%. After applying the proposed techniques, the nonuniformity is unrecognizable and the OLED display panel´s lifespan is highly extended.