JP2007271971A5 - - Google Patents

Claims (5)

An organic EL element, a driving TFT, a capacitor provided between the gate and source of the driving TFT, first, second and third feeders for supplying a constant potential, and a signal to which a signal current source is connected An organic EL display device, wherein one electrode of the organic EL element is connected to the first power supply line, and the other electrode of the organic EL element is connected to a drain of the driving TFT Because
(1) connecting the gate of the driving TFT to the third power supply line, connecting the source of the driving TFT to the signal line, and flowing the signal current between the source and drain of the driving TFT;
(2) The step of separating the gate of the driving TFT from the third feeder and maintaining the voltage across the capacitor in the step of flowing the signal current;
(3) a step of separating the source of the driving TFT from the signal line; and (4) connecting the source of the driving TFT to the second power supply line, and connecting the first power supply line and the second power supply line. A method for driving an organic EL display device, comprising a step of passing a current through the driving TFT and the organic EL element in between. Before Symbol first and the voltage between the third power supply line, when the signal current source supplying the signal current to minimize the luminance of the organic EL display device to the signal line, the step of ((1) The voltage between the electrodes of the organic EL element in FIG. + The voltage between the gate and source of the driving TFT) is greater than or equal to the signal current source, and the signal current is applied to the signal line to maximize the luminance of the organic EL display device. 2. The driving method of the organic EL display device according to claim 1 , wherein the voltage is not more than (voltage between both electrodes of the organic EL element in the step (1) + gate-source voltage of the driving TFT) when supplied. A voltage between the first and second feed line, when the supply a signal current by the signal current source to maximize the luminance of the organic EL display device to the signal line, in the step of ((1) The voltage between the source and drain of the driving TFT + the voltage between both electrodes of the organic EL element in the same step) and above (the voltage between the source and drain of the driving TFT in the step (1) + the step in the same step) 2. The driving method of the organic EL display device according to claim 1 , wherein the driving voltage is less than a voltage between both electrodes of the organic EL element + a threshold voltage of the driving TFT. When the signal current source supplies a signal current that maximizes the luminance of the organic EL display device to the signal line, the potential of the signal line in the step (1) is the potential of the second feeder line. When equal Kusuru method for driving an organic EL display device according to claim 3. An organic EL element, a driving TFT, a capacitor provided between the gate and source of the driving TFT, first, second and third feeders for supplying a constant potential, and a signal to which a signal current source is connected An organic EL display device, wherein one electrode of the organic EL element is connected to the first power supply line, and the other electrode of the organic EL element is connected to a drain of the driving TFT. ,
A first switch provided between the gate of the driving TFT and the third power supply line; a second switch provided between a source of the driving TFT and the signal line; and the driving TFT. An organic EL display device, further comprising: a third switch provided between the source of the first power supply line and the second power supply line; and means for controlling opening and closing of the first to third switches.