Patent ID: 7675494

Claim:
An organic light-emitting device comprising: a light emitting diode that emits light by a signal current; a driving thin film transistor connected between a source voltage and the light emitting diode and connected at its drain to the light emitting diode and a current source, and that supplies the signal current to the light emitting diode depending on display data; a storage capacitor connected between the source voltage and a gate of the driving thin film transistor, and that stores the display data depending on a display data signal; a first switching unit connected between the drain of the driving thin film transistor and a data driver and connected at its gate with a first scan line, wherein the first switching unit selects the data signal; a second switching unit connected between the gate and the drain of the driving thin film transistor and connected at its gate with a second scan line wherein the second switching unit drives the driving thin film transistor; a third switching unit directly connected between the drain of the driving thin film transistor and the light emitting diode and connected at its gate with a third scan line, wherein the third switch unit selects the signal current applied to the light emitting diode; and a fourth switching unit directly connected between the drain of the driving thin film transistor and the current source and connected at its gate with the third scan line, wherein the fourth switching unit selects a reference current applied to the current source, wherein the third and fourth switching units are of a same transistor type and forms a current mirror circuit.