1.  Technical Field
The present invention relates to a technique for driving light emitting elements such as organic electroluminescent (EL) elements. 
2.  Related Art
In light emitting devices in which a driving current supplied to a light emitting element is controlled by a driving transistor, variations in the electrical characteristics (deviations from target values or variations between elements) of the driving transistor become an issue.  JP-A-2007-310311 discloses a technique of setting a gate-source voltage of a driving transistor to the threshold voltage of the driving transistor and then changing the gate-source voltage to a voltage corresponding to a gradation, thereby compensating for the variations (and accordingly, the variation in the amount of the driving current) in the threshold voltage and the mobility of the driving transistor. 
However, the effective compensation for the variations in the driving current by the technique disclosed in JP-A-2007-310311 is limited to cases where a specific gradation is specified, and depending on the gradations, in some cases, the variations in the driving current cannot be corrected.