1. Field of the Invention
Embodiments relate to an organic light emitting display device and a driving method thereof.
2. Description of the Related Art
Recently, various flat panel display devices capable of reducing weight and volume, which are disadvantages of a cathode ray tube, have been developed. These flat panel display device include a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP), an organic light emitting display (OLED), and the like.
Among them, the organic light emitting display device, which displays an image using an organic light emitting diode generating light by recombination between electrons and holes, has advantages of rapid response speed and low power consumption.
The organic light emitting display device includes a plurality of data lines, a plurality of scan lines, and a plurality of pixels arranged in the form of a matrix at intersections of the power lines. The pixels generally each include an organic light emitting diode and a driving transistor controlling an amount of current flowing to the organic light emitting diode. The above-mentioned pixel supplies current from the driving transistors to the organic light emitting diode corresponding to a data signal to generate light having a predetermined luminance.
However, in the pixel in the related art, in the case of representing a white grayscale after having implemented a black grayscale as shown in FIG. 1, a generated light may have luminance lower than desired luminance during periods of about two frames. In this case, in each pixel, the image is not represented in the desired luminance corresponding to the grayscale, which, in turn, luminance uniformity deteriorates, thereby causing image quality of moving pictures to deteriorate.
According to an experimental result, deterioration of a response characteristic is caused by a characteristic of a driving transistor included in the pixel. In other words, a threshold voltage of the driving transistor is shifted corresponding to voltage applied to the driving transistor during the previous period of frame, and, due to the shifted threshold voltage, light having the desired luminance is not generated in a current frame.