Organic light-emitting diode display pixel circuit employing double-gate low-temperature poly-Si thin-film transistor and metal-oxide thin-film transistors

摘要

An organic light-emitting diode (OLED) display pixel circuit composed of a double-gate (DG) low-temperature polycrystalline silicon (LTPS) thin-film transistor (TFT) and metal-oxide (MO) TFTs is reported. Two control lines used to initialize the gate-to-source bias (V-GS) of the driving TFT in the conventional pixel circuit are eliminated by modulating the bottom gate bias (V-BS) of the DG-LTPS TFT. Low leakage current of MO TFT enables us to adopt the simultaneous-emission scheme for arbitrary compensation time setting and 1-Hz frame rate driving for low power consumption without flicker. The proposed circuit exhibits better compensation results and smaller area compared with the conventional low-temperature polycrystalline silicon and oxide (LTPO) pixel circuit. The pixel density of 538 pixels per inch (ppi) has been obtained employing 2-mu m design rule.