Patent ID: 7432891
Filing Date: 2008-10-07
Classification: G09G

Abstract:
1. A driving circuit for an image point of an image screen which has an organic light-emitting diode, comprising a capacitor; a feedback coupling; a first thin film transistor as a current-driving transistor for the diode; a second transistor which is connected by a current-conducting electrode with a gate of said first transistor and by a second current-conducting electrode with a data conductor and by its gate electrode with a scanning signal conductor; a third thin film transistor which during driving its gate through a driving conductor taps a diode driving current at an output of said first current-driving transistor and supplies a current measuring- and voltage regulating circuit, said current measuring- and voltage regulating circuit providing to the data conductor a voltage signal which is dependent on a current measuring result and a voltage comparison, so that the diode during driving of said gate of said third transistor due to its non-linear switching characteristic acts as a switch for a current deviation in said current measuring- and voltage regulating circuit.