Shared Pixel Compensation Circuit for AM-OLED Displays

In the case of active-matrix OLED (AM-OLED) displays, the nonuniformity of gray levels is a severe problem that is caused by the nonuniformity of the mobility and the threshold voltage (VT) of the driver thin-film transistors (TFTs); therefore, many compensation circuits and driving techniques were proposed. However, those proposed pixel circuits usually required more than three TFTs and a number of capacitors per pixel. In addition, it was very difficult to preserve enough of the emission area to accommodate the bottom-emitting OLED structure, and such a high number of electrical parts diminished the production yield of the displays.