Fast Progressive Compensation Method for Externally Compensated AMOLED Displays

Abstract

The externally compensated display system has been proved to have greater potential to completely solve aging and uniformity issues of the AMOLED display system than the internally compensated display system. However, the traditional compensation method is time consuming and responses slowly to the mobility change of TFT. The traditional compensation method performs calibration during the inter-frame blanking period, the length of which is limited. Only a few rows of pixel circuits can be calibrated per frame. Furthermore, each pixel circuit needs multiple times of calibration to reach compensated state. In this article, a fast progressive compensation method is proposed. The calibration of a row of pixel circuits is performed K rows ahead of the display line during the display data updating period. By doing so, the proposed fast progressive compensation method can approach compensated state faster than the traditional method because display data updating period is significantly longer than the inter-frame blanking period. For the case of 10% inter-frame blanking period and 20 $\mu \text{s}$ waiting delay for feedback data line to be stable, the proposed method reduces the compensation time by ~14x than the traditional method.

Keywords

• Thin-film transistor (TFT)
• external compensation
• fast calibration