Patent ID: 8390653

Claim:
An electroluminescent (EL) pixel for correcting light emission efficiency of an EL element, comprising: (a) a driving transistor for supplying electric current, the driving transistor having a mutual conductance and a threshold voltage; (b) the EL element for emitting light in response to the electric current, the EL element having an efficiency; (c) a detection unit for detecting a parameter which reflects the mutual conductance of the driving transistor; and (d) a correction unit for receiving a data signal representing a target brightness, generating a correction data signal using the data signal and the detected parameter, and supplying the correction data signal to the driving transistor, so that the driving transistor supplies electric current in accordance with the correction data signal, wherein the correction data signal overcompensates for variation in the threshold voltage of the driving transistor so that the correction data signal compensates for degradation of the efficiency of the EL element, wherein the parameter is the threshold voltage of the driving transistor, or a gate voltage necessary for causing a selected electric current to flow in the driving element, or a voltage for charging or discharging of a fixed capacitance in a fixed time period by the driving element, and wherein the correction unit includes a storage capacitor and a correction thin film transistor having a gate, a source and a drain, the detected parameter is applied to the drain or gate of the correction thin film transistor, and the data signal is applied to the source of the correction thin film transistor, so that the storage capacitor is charged with the correction data signal.