1. Field of the Invention
The present invention relates to a pixel and an organic light emitting display device using the same, and more particularly, to a pixel and an organic light emitting display device using the same that can save manufacturing costs and stably express a black gray level.
2. Description of Related Art
Recently, there have been various types of flat panel display devices capable of reducing their weight and volume, which are unfavorable in cathode ray tubes. The flat panel display devices include, for example, liquid crystal displays, field emission displays, plasma display panels and organic light emitting display devices.
Among these flat panel display devices, the organic light emitting display device displays images using an organic light emitting diode (OLED) that emits light through the recombination of electrons and holes. The organic light emitting display device has a fast response speed and is driven with low power consumption. Typically, in an organic light emitting display device a current corresponding to a data signal is supplied to an OLED using a driving transistor formed for each pixel, so that light is emitted from the OLED.
To this end, each of the pixels includes a storage capacitor to be charged with a voltage corresponding to a data signal supplied to a data line. The storage capacitor in turn supplies the charged voltage to a driving transistor. Therefore, in order to display an image with a desired gray level, the voltage corresponding to the data signal needs to be precisely charged in the storage capacitor.
However, in a conventional organic light emitting display device, a desired voltage may not be precisely charged in the storage capacitor. More specifically, a data signal is supplied to a storage capacitor by means of a data line. Here, a parasitic capacitor exists in the data line, and therefore, the data signal supplied to the data line is supplied to the storage capacitor while charging the parasitic capacitor. In this case, a voltage corresponding to a desired data signal is not charged in the storage capacitor due to charge sharing of the parasitic capacitor and the storage capacitor. Particularly, in the event that black is expressed in the organic light emitting display device, a gray scale is expressed, and display quality is degraded.