US Patent 9230996 Light-emitting device

A light-emitting device capable of suppressing variation in luminance among pixels is provided. A light-emitting device includes a pixel and first and second circuits. The first circuit has a function of generating a signal including a value of current extracted from the pixel. The second circuit has a function of correcting an image signal by the signal. The pixel includes at least a light-emitting element and first and second transistors. The first transistor has a function of controlling supply of the current to the light-emitting element by the image signal. The second transistor has a function of controlling extraction of the current from the pixel. A semiconductor film of each of the first and second transistors includes a first semiconductor region overlapping with a gate, a second semiconductor region in contact with a source or a drain, and a third semiconductor region between the first and second semiconductor regions.