A light emitting device capable of performing signal electric current write-in
operations at high speed and without dispersion in the characteristics of TFTs
structuring pixels influencing the brightness of light emitting elements is provided.
The gate length L of a transistor in which an electric current flows during write-in
of a signal electric current is made shorter than the gate length L of a transistor
in which electric current supplied to EL elements flows during light emission,
and high speed write-in is thus performed by having a larger electric current flow
than the electric current flowing in conventional EL elements. A converter and
driver transistor (108) is used for signal write-in. By using the converter
and driver transistor (108) and a driver transistor (107) when supplying
electric current to a light emitting element during light emission, dispersion
in the transistor characteristics can be made to have less influence on brightness
than when using a structure in which write-in operations and light emission operations
are performed using different transistors.
