1. Field of the Invention
The present invention relates to a display device and a method of controlling the display device, and more particularly to a display device and a control method that is capable of reducing the deterioration of a thin film transistor.
2. Description of the Related Art
Recently, organic light emitting diodes (OLEDs) have become popular among flat panel displays. The popularity of OLEDs is at least partly due to characteristics such as low-voltage driving, light weight, slim shape, wide angle view and high-speed response. In the OLED substrate are formed a plurality of thin film transistors (TFTs) to drive the OLED, an anode electrode forming a pixel on the TFT, and a cathode electrode that generates a reference voltage. A Voltage is applied across both of the electrodes so that holes and electrons are coupled to generate excitons. Such excitons emit light while the excitons are transferred to a ground state. The light emission occurs in an emitting layer between the electrodes where the holes and the electrons combine. The OLED displays an image by adjusting the light emission.
In general, the plurality of TFTs are formed on the OLED substrate. Each pixel is provided with a switching transistor connected to a data line and a driving transistor connected to a driving voltage line.
The TFTs of the OLED progressively deteriorate with driving time. This deterioration can result in a serious problem of a predetermined voltage not being applied to the pixel electrode. Particularly, the higher the data voltage, the higher is the driving voltage. Thus, the voltage that is actually applied may be different from the “normal voltage” that should be applied to the pixel electrode. Also, the amount of a voltage or current applied to the pixel electrode may deviate from the normal range due to the deterioration of the light emitting layer made of organic materials. Due to these deteriorations of the TFTs and/or the light emitting layer, the brightness of a display device may be non-uniform and may decrease with time. It is desirable to prevent such adverse effects on the brightness of a display device.