Display device and driving method thereof

A method for driving a display device comprising a controller to process an input image signal and an input control signal to control output a digital image signal, a gray voltage generator to generate a gray reference voltage, and a data driver to generate gray voltages based on the gray reference voltage, the method comprising:

• generating a first gray reference voltage with respect to the input image signal or a second gray reference voltage with respect to an insertion gray, the generation being performed according to a selection signal included in the control signal;
• receiving one of the first gray reference voltage or the second gray reference voltage;
• and
• dividing the received gray reference voltage to generate the gray voltages, and selecting gray voltage among the generated gray voltages to output a data voltage.

A method for offsetting an afterimage of a display device, the method comprising:

• determining series of image signals and characteristics of the display device whether an afterimage is occurred;
• defining a gray reference voltage according to a degree of the afterimage and the characteristics of the display device;
• selecting, using a selection signal, a gray voltage based on the defined gray reference voltage, wherein the selection corresponds to the determined afterimage of the image signals and the characteristics of the display device, wherein the selected gray voltages are controlled by the selection signal which comprises a black data voltage comprising various tones of gray;
• and
• applying the selected gray voltages, using the selection signal, to the image signals to offset the afterimage, wherein the selected gray voltages are fed to a driver to control displaying images.