Method for driving display element and method for driving display device
View Patent ↗Disclosed herein is a method for driving a display element including a current-driven light emitting part and a drive circuit, the drive circuit including a write transistor, a drive transistor, and a capacitive part, the method including the steps of: executing threshold voltage cancel processing of changing potential of the second node toward potential obtained by subtracting threshold voltage of the drive transistor from potential of the first node in a state in which the potential of the first node is kept; and executing write processing of applying a video signal from the data line to the first node via the write transistor turned to an on-state by a scan signal from the scan line.
1. A display device including:
a current-driven light emitting part;
a drive circuit, the drive circuit including a write transistor, a drive transistor, and a capacitive part, in a display element; and
an additional capacitive element between the first electrode of the light emitting part and the capacitive part,
wherein,
the drive circuit is configured to (a) execute correction processing of extracting a current flow through the drive transistor to the capacitive part, and (b) execute write processing of writing a video signal from the data line to the capacitive part via the write transistor,
the correction processing is executed in a state in which a first reference voltage is applied to a first electrode of the light emitting part,
subsequently the write processing is executed in a state in which a second reference voltage lower than the first reference voltage is applied to the first electrode of the light emitting part,
the light emitting part and the drive transistor are connected between a first power supply line and a second power supply line so as to form a current path when the light emitting part emits light, wherein:
V cat-H denotes the first reference voltage,
V Cat-L denotes the second reference voltage,
V Sig-Max denotes a maximum value that is possibly taken by the video signal,
V Sig-min denotes a minimum value that is possibly taken by the video signal,
c A denotes capacitance of the capacitive part,
c B denotes capacitance of the additional capacitive element,
V Ofs denotes voltage applied to the capacitive part during the correction processing, and
a relationship V cat-H −V Cat-L =((V Sig-Max +V Sig-min )/2 −V Ofs )·c A /c B holds true.
2. The display device according to claim 1 , wherein the electrode of the light emitting part is a cathode electrode of the light emitting part, and one node of the capacitive part is connected to an anode electrode of the light emitting part.
3. The display device according to claim 1 , wherein the additional capacitive element is a capacitive component of the light emitting part.
4. A method for driving a display element according to claim 1 , comprising:
first, executing a pre-processing of initializing the potential stored in the capacitive part so that the potential stored in the capacitive part surpasses the threshold voltage of the drive transistor and stored in the additional capacitive element does not surpass threshold voltage of the light emitting part,
second, executing threshold voltage cancel processing,
third, thereafter, executing a write processing, and
fourth, placing one node of the capacitive part in a floating state by switching the write transistor to an off-state, and driving the light emitting part by making a current dependent on the potential stored in the capacitive part flow through the light emitting part via the drive transistor.
5. The method for driving a display element according to claim 1 , wherein the light emitting part is formed of an organic electroluminescence light emitting part.