A low-power driving scheme for a-Si:H active-matrix organic light-emitting diode displays

Abstract

This paper describes a low-power driving scheme along with a pixel circuit based on hydrogenated amorphous silicon (a-Si:H) technology for active matrix organic light emitting diode (AMOLED) displays. The driving scheme can provide different current levels for the OLED while compensating for long-term (and gradual) instabilities caused by material defect metastability which will make it amenable for use in AMOLED displays. Moreover, since the threshold voltage is known in this method, it can be used to compensate for the time-dependent errors of the charge injection and clock feed-through effects. Therefore, the error for a 3V shift in the VT of T1 is almost zero. More importantly, it has low power consumption because the line capacitance is charged just one time during the programming cycle. For example, the total power consumption of a QVGA array (240*320) is expected to be less than 1.5W.