A New Compensation Method for Emission Degradation in an AMOLED Display Via an External Algorithm, New Pixel Circuit, and Models of Prior Measurements

A new external algorithm with sensing circuit are proposed to compensate AMOLED display degradation. The compensation is enabled by first evaluating degradation level of OLEDs based on the OLED anode voltages detected by a newly-designed sensing subcircuit. According to sensed voltages, the external algorithm selects appropriate built-in models to compensate OLED degradation with the aim to achieve expected OLED emitted luminance. The models are established based on prior measurements to prescribe the relations between luminance and current (L-I) and luminance and voltage (L-V) of each OLED. In this way of compensation, the proposed method is able to incorporate negative effects of OLED degradation aggravation while increasing driving current to compensate the original decay in OLED luminance. Moreover, another algorithm along with the 4T0.5C pixel circuit as presented in prior studies are adopted to compensate process variation in Vth among pixels for improving the emission uniformity of an AMOLED panel. Experiments are conducted by combining the external algorithm with sensing circuit and the pixel circuit to validate the performances of compensating and alleviating OLED degradation.