49.4: Two TFT Pixel Circuit with Non-Uniformity Suppress-Function for Voltage Programming Active Matrix OLED Displays

Abstract

We proposed the world's first two TFT pixel circuit with an inter-pixel non-uniformity suppress-function for the analog voltage programming to assist in the realization of small pixel bottom emission OLED displays. The pixel circuit provides larger OLED fill factor. We fabricated a 2.5 inch 240 (V) x 960 (H) pixel monochrome bottom emission display.

A video data correction method for the non‐uniform electro‐optical characteristics of the pixels in AMOLED displays

“…The current-sensing voltage-feedback method [9] and the voltage-programming-with-transimpedance- feedback method [10] can compensate for both the threshold voltage and the mobility variation and does not have a data-charging problem, but its pixel structure and driving method are too complex. The digital driving method [11] uses a driving TFT in the linear region, and the clamped-inverter driving method [12] uses an inverter to control the emission time, so the electrical-characteristic variation of TFT rarely affects the deviation of the emission current. It is sensitive, however, to OLED degradation and powerline IR drop because the anode voltage variation of OLED directly changes OLED's emission current.…”