US Patent 7129917 Light-emitting device

There is provided an EL light-emitting device with less uneven brightness. When a drain current of a plurality of current controlling TFTs is Id, a mobility is μ, a gate capacitance per unit area is Co, a maximum gate voltage is Vgs(max), a channel width is W, a channel length is L, an average value of a threshold voltage is Vth, a deviation from the average value of the threshold voltage is ΔVth, and a difference in emission brightness of a plurality of EL elements is within a range of ±n %, a semiconductor display device is characterized in that