To provide a light emitting device without nonuniformity of luminance, a correcting
circuit for correcting a video signal supplied to each pixel to a light emitting
device. The correcting circuit is stored with data of a dispersion of a characteristic
of a driving TFT among pixels and data of a change over time of luminance of a
light emitting element. Further, by correcting a video signal inputted to the light
emitting device in conformity with a characteristic of the driving TFT of each
pixel and a degree of a deterioration of the light emitting element based on the
over-described two data, nonuniformity of luminance caused by a deterioration of
an electroluminescent layer and nonuniformity of luminance caused by dispersion
of a characteristic of the driving TFT are restrained.
