Patent ID: 8248334
Filing Date: 2012-08-21
Classification: G09G

Abstract:
1. A method of driving an organic electroluminescence emission portion, in which a drive circuit for driving an organic electroluminescence emission portion includes (A) a drive transistor including source/drain regions, a channel formation region, and a gate electrode, (B) a write transistor including source/drain regions, a channel formation region, and a gate electrode, and (C) a capacitor portion including a pair of electrodes; in said drive transistor, (A-1) one of said source/drain regions is connected to a power source portion, (A-2) the other of said source/drain regions is connected to an anode electrode provided in said organic electroluminescence emission portion, and is connected to one of said pair of electrodes of said capacitor portion for forming a second node, and (A-3) said gate electrode is connected to the other of said source/drain regions of said write transistor, and is connected to the other of said pair of electrodes of said capacitor portion for forming a first node; in said write transistor, (B-1) one of said source/drain regions is connected to corresponding one of data lines, and (B-2) said gate electrode is connected to corresponding one of scanning lines; by using said drive circuit, there are performed the steps of: (a) executing preprocessing for initializing a potential at said first node and a potential at said second node so that a difference in potential between said first node and said second node exceeds a threshold voltage of said drive transistor, and a difference in potential between said second node and a cathode electrode provided in said organic electroluminescence emission portion does not exceed a threshold voltage of said organic electroluminescence emission portion; (b) executing threshold voltage canceling processing for applying a higher voltage than that obtained by subtracting the threshold voltage of said drive transistor from the potential at said first node from said power source portion to one of said source/drain regions of said drive transistor in a state of holding the potential at said first node for changing the potential at said second node toward the potential obtained by subtracting the threshold voltage of said drive transistor from the potential at said first node; (c) executing write processing for supplying a video signal from the corresponding one of said data lines to said first node through said write transistor; and (d) turning OFF said write transistor to set said first node in a floating state for causing a current corresponding to a value of the difference in potential between said first node and said second node to flow from said power source portion to said organic electroluminescence emission portion through said driving transistor; said driving method including the steps of applying a first node initialization voltage to corresponding one of said data lines, and supplying the video signal instead of the first node initialization voltage for a predetermined scanning time period, applying the first node initialization voltage from the corresponding one of said data lines to said first node through said write transistor held in an ON state for initializing the potential at said first node in said step (a), and holding a state of applying the first node initialization voltage from the corresponding one of said data lines to said first node through said write transistor held in an ON state for holding the potential at said first node in said step (b); wherein said write transistor is turned ON prior to a commencement of the scanning time period for which said step (a) is intended to be performed in accordance with a signal from the corresponding one of said scanning lines, and said step (a) is performed.