35.1: High Resolution AMOLED Pixel Using Negative Feedback Structure for Improving Image Quality

Abstract

An active matrix organic light emitting diode (AMOLED) pixel structure is proposed to improve image quality of high resolution small sized displays. The proposed pixel structure increases luminance uniformity by decreasing the distortion of the voltage in the storage capacitors using negative feedback structure. The simulation results show that the distortion of the voltage in the storage capacitors with negative feedback structure decreases to 55.3% compared to that without negative feedback structure and the emission current error of the proposed pixel structure ranges from -0.71 LSB to 0.56 LSB when the threshold voltage of the driving TFT varies from -0.2 V to 0.2 V.

New pixel driving circuit using self‐discharging compensation method for high‐resolution OLED micro displays on a silicon backplane

“…There have been proposed pixel compensation methods using negative feedback from V OLED. However, these methods may cause an emission current degradation because the V OLED gradually increases as the OLED emits light. An emission current degradation may affect the luminance lifetime of OLED displays.…”

Pixel structures using the negative feedback method for high‐resolution active matrix organic light‐emitting diode displays

“…The capacitive coupling always cancels the gate voltage distortion because when the gate voltage of the driving TFT is distorted, the anode voltage of the OLED changes in the opposite direction of the gate voltage distortion. This operation contributes to the negative feedback effect that reduces the gate voltage distortion of the driving TFT …”

“…Simultaneous emission driving method is also not applicable for mobile application because of large power consumption and reduced lifetime of panel due to the short emission time. The negative feedback method has been proposed to reduce the gate voltage distortion of the driving TFT, in spite of the decreased storage capacitance . In this paper, two pixel structures (proposed pixel structures A and B) using the negative feedback method are reported.…”

“…The negative feedback method has been proposed to reduce the gate voltage distortion of the driving TFT, in spite of the decreased storage capacitance. 13 In this paper, two pixel structures (proposed pixel structures A and B) using the negative feedback method are reported. The proposed pixel structures A and B improve image quality by decreasing the voltage distortion in the storage capacitor with the negative feedback method although the storage capacitance is small.…”

“…This operation contributes to the negative feedback effect that reduces the gate voltage distortion of the driving TFT. 13 Therefore, the main problem of the proposed pixel structure A causing the emission current error is the voltage variation of node A because the voltage of node A is V anode in the emission phase.…”