A pixel circuit and a gate driver on array for light-emitting display are presented. By simultaneously utilizing top-gate n-type oxide and p-type lowtemperature polycrystalline silicon (LTPS) thin-film transistors (TFTs), the circuits provide high refresh rate and low power consumption. An active-matrix LED (AMOLED) panel with proposed circuits is fabricated, and driving at various refresh rate ranging from 1 to 120 Hz could be achieved.

We report the high performance top gate IGZO‐TFT for OLED display. By optimizing the conditions of process, we fabricated the transistor with mobility from 7 to 32 cm2 /Vs with enhanced threshold voltage. They also have reliability PBT/NBT enough to use application. Finally, the prototype 12.3” ultrawide flexible OLED display was successfully demonstrated.

An AMOLED panel using hybrid backplane technology based on p-type low temperature polycrystalline silicon (p-LTPS) and n-type indium-galliumzinc-oxide (n-IGZO) thin-film transistors (TFTs) has been successfully manufactured. New pixel and Gate-on-Array (GOA) circuits were designed and fabricated using this technology. GOA with CMOS inverter is realized by utilizing both IGZO and p-LTPS. The hybrid backplane AMOLED panel can operate between 1 and 120 Hz, which enables both high refresh rate and low standby power display applications. Furthermore, the AMOLED panel lifetime has markedly enhanced by improving IGZO TFT's uniformity and reliability.

IGZO TFT with the same on current as n-LTPS was fabricated. The saturation on current reached 1 mA, and the off-state leakage current was below 1 pA. The Vth shift under PBT / NBT stress test for the IGZO TFT was 0.1 / 0.1 V, respectively, which was better compared to the n-LTPS. Furthermore, the IGZO TFT showed an ideal Id-Vd curve (output characteristics) without any kinks. These results indicate that, a variety of backplanes, from small size smartphones to large area TVs, are possible to be made in a single factory of IGZO.

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