Patent ID: 7592652

Claim:
A light emitting device comprising: a pixel comprising a first transistor, a second transistor and a light emitting element; a first wiring electrically connected to a gate electrode of the first transistor; a second wiring electrically connected to one of impurity regions of the first transistor; and a third wiring electrically connected to one of impurity regions of the second transistor, wherein another one of impurity regions of the second transistor is electrically connected to the light emitting element, wherein the first transistor and the second transistor have a same conductivity type, wherein the first wiring is parallel to the third wiring, wherein a length of a period in which the light emitting element is in a non light-emitting state is controlled by controlling an electric potential of the third wiring, and wherein each of the first transistor and the second transistor comprises a crystalline semiconductor film.