PIXEL CIRCUIT OF ORGANIC LIGHT EMITTING DEVICE OF COMPENSATING THRESHOLD VOLTAGE

摘要

A pixel circuit of an organic light emitting device for compensating for a threshold voltage is provided to improve non-uniformity of brightness due to the difference of a threshold voltage of a driving transistor in each pixel. A first switching transistor(Q1) transmits a data signal to a first node according to a selection signal. A second switching transistor(Q2) is connected between a positive power voltage and the first node and performs on/off operation according to the selection signal. A third switching transistor(Q3) performs on/off operation according to the selection signal and is connected to a second node. A driving transistor(Q5) is connected between the firs and second nodes and generates a driving current corresponding to the data signal. A threshold voltage compensating transistor(Q4) is connected between the second node and the third node and compensates for the threshold voltage of the driving transistor. A storage capacitor is connected between the third node and the positive power voltage and stores the threshold voltage and the data signal. The organic light emitting diode is connected between a third switching transistor and the negative power voltage and performs the light emission operation by the driving current.