Patent ID: 8264428

Claim:
A pixel driving method for an organic light emitting device, comprising: charging a data voltage supplied through a data line to a storage capacitor and driving an N-channel switching transistor while cutting off supply of an upper power supply voltage to an organic light emitting diode in data voltage programming period; and powering the organic light emitting diode to emit light by driving a first N-channel driving transistor by the data voltage charged onto the storage capacitor while supplying the upper power supply voltage to the light emitting diode in data voltage emission period, wherein a switching control signal is supplied to a gate of a second N-channel driving transistor during the data voltage programming period and thus supply the upper power supply voltage to the light emitting diode is cut off, wherein one side of the storage capacitor is connected to a gate of the first N-channel driving transistor, and another side of the storage capacitor is connected to a lower power supply voltage, wherein the first N-channel driving transistor has a drain connected to a source of the second N-channel driving transistor, and a source connected to the lower power supply voltage, wherein the second N-channel driving transistor has a drain connected to a cathode of the light emitting diode, and a source connected to the drain of the first N-channel driving transistor, wherein when a data voltage programming operation is completed, a first node where one side of the storage capacitor and the gate of the first N-channel driving transistor are connected to each other is in an electrical floating status, wherein a voltage of a second node is changed from the upper power supply voltage supplied during the data voltage emission period, the second node where the source of the first N-channel driving transistor and the lower power supply voltage are connected to each other, wherein when the voltage of the second node is changed during the data voltage emission period, the voltage of the first node is changed by coupling of the storage capacitor, thereby a voltage between gate and source terminals of the first N-channel driving transistor is not changed during the data voltage emission period, and wherein a driving current of the organic light emitting diode is not influenced by the second node, and is influenced by the data voltage stored in the storage capacitor.