16‐3: A Fast TFT Threshold Voltage Sensing Method Based on Iterative Feedback

Abstract

In this paper, we present a fast TFT threshold voltage extraction method adapting iterative feedback. Using this method we can obtain relative TFT threshold voltage Vth of all pixels in the AMOLED display. According the relative TFT threshold voltage, we can compensate the driving data to significantly improve the uniformity of AMOLED display.

[Paper] Development of an External Compensation Technique for Burn-in Degradation in a 4K Flexible AMOLED Display

“…To compensate for the instability of driving TFTs, several approaches have been proposed [4][5][6][7][8][9][10][11] . Among them, in-pixel compensation circuits are unsuitable for large displays because they require more transistors, and the manufacturing process is complicated.…”

“…Among them, in-pixel compensation circuits are unsuitable for large displays because they require more transistors, and the manufacturing process is complicated. External compensation circuits [7][8][9][10][11][12][13] are one appropriate method for large ultra-high-definition displays because they are comparatively simple pixel circuits and contain a limited number of transistors. Although they need complex signal processing, large displays, such as TVs, usually have a high-performance processor.…”

A Novel Real-Time TFT Threshold Voltage Compensation Method for AM-OLED Using Double Sampling of Source Node Voltage

“…Several effective compensation methods have been proposed [9]- [12]. Among them, sensing and applying V th to the compensation has become mainstream because TFTs' threshold voltage (V th ) variation is considered the major factor that affects the luminance uniformity in OLED display [12], [13].…”

“…Then analog-to-digital converter in the display driver integrated circuit detects the TFT parameters. Normally external compensation method takes tens of milliseconds to detect V th of each TFT [6], [13]. Therefore, real-time TFT degradation cannot be compensated during display operation.…”

“…This article proposes a compensation method can be carried out within a vertical blank. Many studies about real-time V th compensation have been conducted such as fast methods using iterative feedback [13], linear charging method [18], and current sensing [19]. However, these methods take more than the vertical blank time of the latest display products, or the non-uniform mobility is not considered.…”