Light emitting device, driving method of light emitting device and electronic device

A light-emitting device comprising:

• a signal line and a scan line over a substrate;
• a first transistor and a second transistor over the substrate, each comprising:
• a first electrode including a tapered cross section;
• a first insulating film over the first electrode;
• a semiconductor film over the first insulating film;
• a second insulating film over the semiconductor film;
• a second electrode over the second insulating film;
• and
• a light-emitting element over the substrate,
• wherein the signal line is electrically connected to the semiconductor film of the first transistor,
• wherein the scan line is electrically connected to the first electrode and the second electrode of the first transistor,
• wherein the first electrode and the second electrode of the second transistor are electrically connected to the semiconductor film of the first transistor, and
• wherein the light emitting element is electrically connected to the semiconductor film of the second transistor.

A light-emitting device comprising:

• a signal line and a scan line over a substrate;
• a first transistor and a second transistor over the substrate, each comprising:
• a first electrode;
• a first insulating film including a pair of laminated insulating films over the first electrode;
• a semiconductor film over the first insulating film;
• a second insulating film over the semiconductor film;
• a second electrode over the second insulating film;
• and
• a light-emitting element over the substrate,
• wherein the signal line is electrically connected to the semiconductor film of the first transistor,
• wherein the scan line is electrically connected to the first electrode and the second electrode of the first transistor,
• wherein the first electrode and the second electrode of the second transistor are electrically connected to the semiconductor film of the first transistor, and
• wherein the light emitting element is electrically connected to the semiconductor film of the second transistor.