Transistor technologies and pixel circuit design for efficient active-matrix organic light-emitting diode displays

Following the advent of the digital multi-media era and the popularity of the internet, high-resolution flat-panel displays (FPDs) are becoming the central feature of many consumer products, from camcorders, mobile/smart phones, to notebook PCs. The FPD industry has been dominated by the liquid crystal displays (LCDs), which are advancing so rapidly that it seems difficult for other technologies to compete in the marketplace, despite all the enthusiasm and innovation emerging from research laboratories in both universities and industry for decades. On the other hand, with the continuous development of related materials and device architectures for efficient and stable organic light emitting diodes (OLEDs), the commercialization of active matrix organic light emitting diode (AMOLED) display products is accelerating [1]. AMOLED displays provide a set of attractive attributes to be used for high-quality video applications, such as excellent contrast ratio, ultra-fast response, vivid visual full-color appearance, and mechanically, a thinner and simpler structure compared to LCDs. AMOLEDs are rapidly expanding their market share for small-sized mobile applications since their mass production launch in 2007, and are also expected to enter the arena of larger-area displays for TVs soon [2].