Patent ID: 8294640

Claim:
A light emitting device comprising: a first pixel including a first light emitting element; a second pixel including a second light emitting element; a first current source circuit; a second current source circuit electrically connected to the first current source circuit; a third current source circuit; and a fourth current source circuit electrically connected to the third current source circuit, wherein the second current source circuit is electrically connected to the first pixel, wherein the fourth current source circuit is electrically connected to the second pixel, wherein the first current source circuit comprises: a first power source line; a second power source line; a transistor; a first switch; a second switch; a third switch; and a fourth switch, wherein a first terminal of the first switch is electrically connected to the first power source line, wherein a second terminal of the first switch is electrically connected to a first terminal of the third switch, and one of a source and a drain of the transistor, wherein the other of the source and the drain of the transistor is electrically connected to a first terminal of the second switch, wherein a second terminal of the second switch is electrically connected to the second power source line, wherein a gate of the transistor is electrically connected to a first terminal of the fourth switch, and wherein a second terminal of the fourth switch is electrically connected to the first terminal of the second switch.