A simple pixel circuitry for OLED display

Active OLED are good challenger for becoming the new commonality technology for large displays. Current-controlled pixels that are used in several prototypes are very complex and do not correct all the problems of the use of OLED pixels. This paper presents a different approach to solve these problems. It suggests keeping the pixel circuitry as simple as possible and to put a correction mechanism in the associated VLSI driver. By using this approach, the cost of the screen will decrease and those of its driver will slightly increase. The pixel circuitry transforms the input control voltage to a non-linear mixed current and timing control of the OLED. The driver contains a pipeline circuitry to perform the on-line corrections on the input video stream. A calibration step, during the display manufacturing or maintenance, is used to measure the pixel efficiency and to compute the coefficients to be stored into its flash memories.