Patent ID: 8890860

Claim:
An EL display device comprising: a first capacitor; a first transistor comprising: a gate electrically connected to a scan line; a first terminal electrically connected to a signal line; and a second terminal electrically connected to the first capacitor, wherein the first transistor is turned on by a selection signal from the scan line during a first period so that an image signal from the signal line is held in the first capacitor; a second capacitor; a second transistor comprising: a gate electrically connected to a first control line; a first terminal electrically connected to the first capacitor; and a second terminal electrically connected to the second capacitor, wherein the second transistor is turned on by a first control signal during a second period so that the image signal held in the first capacitor is held in the second capacitor, a third transistor comprising: a gate electrically connected to one electrode of the second capacitor: a first terminal electrically connected to a first power supply line; and a second terminal to which a current is supplied in accordance with the image signal held in the second capacitor, a fourth transistor comprising: a gate electrically connected to a second control line; a first terminal electrically connected to the second terminal of the third transistor; and a second terminal to which the same current that flows through the second terminal of the third transistor is supplied, wherein the fourth transistor is turned on by a second control signal during a third period, and wherein the third period overlaps the first period, and a light-emitting element comprising: a first electrode electrically connected to the second terminal of the fourth transistor; and a second electrode electrically connected to a second power supply line, wherein the light-emitting element emits light in accordance with the same current that flows through the second terminal of the third transistor and the second terminal of the fourth transistor.