Patent ID: 9626906
Date: 2017-04-18
CPC Classifications: G09G

Claim:
1. An organic light emitting display, comprising: a display panel having a plurality of pixels each including an organic light emitting diode, a driving TFT controlling a driving current flowing through the organic light emitting diode depending on a voltage difference between a gate electrode connected to a first node and a source electrode connected to a second node, a first switch TFT switched in response to a first gate signal to apply a data voltage to the first node, a second switch TFT switched in response to a second gate signal to apply an initialization voltage to the second node, and a storage capacitor connected between the first node and the second node; a data driving circuit supplying the data voltage to a data line connected to the plurality of pixels and supplying the initialization voltage to a reference line connected to the plurality of pixels; and a gate driving circuit supplying the first gate signal to a first gate line connected to the plurality of pixels and supplying the second gate signal to a second gate line connected to the plurality of pixels, wherein, in a sensing period during which differences in mobilities of the driving TFTs are compensated, the first gate signal is maintained at an ON level and the second gate signal is maintained at an OFF level, the first and second gate signals are maintained at an OFF level in a light emission period following the sensing period, and a gate voltage and a source voltage of the driving TFT are raised to a voltage level higher than the threshold voltage of the organic light emitting diode while a gate-source voltage of the driving TFT supplied during the sensing period is maintained, and wherein the differences in the mobilities of the driving TFTs are compensated by setting a first falling time of the first gate signal and a second falling time of the second gate signal after compensation, which indicate periods of time required to respectively change the first gate signal and the second gate signal from the ON level to the OFF level, to be 4-6 times longer than the first falling time of the first gate signal and the second falling time of the second gate signal before compensation.