US Patent 7589706 Active matrix light emitting device display and drive method thereof

Drive method and pixel circuits comprising a direct current path between a scan electrode and a data electrode are disclosed. Preferred embodiments of said pixel circuit are provided for the application to convert current signal received from a data electrode to voltage signal for current-control drive. In such preferred embodiments, light emitting device displays are operated in current-control mode without being influenced by variations in threshold voltage of transistor and forward voltage of light emitting element. Further extension and applications are described. Preferred embodiments leading to three-transistor solution of such operation are disclosed.