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This paper proposes amorphous indium–gallium–zinc oxide thin-film transistors (TFTs) four-transistor-two-capacitor (4T2C) pixel circuit in combination with a top-anode organic light-emitting diode (OLED) for the use in 8K4K active-matrix organic light-emitting diode displays (AM-OLEDs). The proposed pixel circuit compensates for driving TFTs threshold voltage (${V} _{\textsf {TH}}$) shifts and mobility variations, ${V} _{\textsf {DD}}$ current–resistance (${I}$ – ${R}$) drops, and ${V} _{\textsf {SS}}~{I}$ – ${R}$ -induced rises. Both the positive and negative ${V} _{\textsf {TH}}$ of the driving TFT can be sensed by the proposed circuit. In this paper, we analyze the impact of the driving TFT compensation time for low gray levels. The current error rates are calculated when TFT mobility variations are considered. The proposed pixel circuit allows an increase in the compensation time to reduce the impact of driving TFT ${V} _{\textsf {TH}}$ and mobility variations on the performance of 4T2C pixel circuit. Conventional two-transistor-one-capacitor, five-transistor-two-capacitor, and proposed 4T2C pixel circuits are simulated and compared in this paper. The proposed pixel 4T2C circuit reduces the current error rates to below 5.79% when the ${V} _{\textsf {TH}}$ shifts of ±2 V, mobility variations of ±10%, ${V} _{\textsf {DD}}~{I}$ – ${R}$ drops of 1 V, and ${V} _{\textsf {SS}}~{I}$ – ${R}$ rises of 1 V are all considered. We show that the proposed 4T2C pixel circuit is suitable for 8K4K AM-OLEDs. [ABSTRACT FROM AUTHOR]

This paper proposes a new hydrogenated amorphous silicon thin-film-transistor-based (a-Si:H TFT-based) gate driver circuit that uses the time-division driving method to ameliorate the display-to-touch crosstalk. The proposed work utilizes a recharging circuit to discharge the voltage on the gate node of the driving TFT when the touch sensing starts with the purpose of suppressing the long-term stress of the driving TFT, and charges the gate node of the driving TFT again before the end of the touch-sensing period to enhance the driving capability of the gate driver circuit. Furthermore, the proposed gate driver circuit achieves bidirectional transmission and an adjustable reporting rate of touch sensing. Measurements verify that the threshold voltage shift of the driving TFT is suppressed from 4.8 to 2.9 V after 120 h of stress at 85 °C and the output waveforms of the proposed gate driver circuits are generated correctly with forward transmission, backward transmission, and pausing in different stages. Moreover, the measured output waveforms are stable without distortion after 360 h reliability test at 85 °C. Consequently, the proposed gate driver circuit is suitable for use in 5.46-in full high-definition panels with in-cell touch technology. [ABSTRACT FROM AUTHOR]

This brief suppresses threshold voltage (${V}_{\text {TH}}$) variations in low-temperature polycrystalline-silicon thin-film transistors (LTPS TFTs) with a new current scaling ratio modulation method for the application of active-matrix organic light-emitting diode displays. With a newly proposed 3T2C LTPS TFT-based pixel circuit, high-current scaling ratios at low gray levels and low ratios at high gray levels are achieved. Thus, the programming time at low gray levels can be reduced, and the driving currents of the OLED are efficiently generated over the entire data range without consuming extra power for the current source. The driving currents are also independent of the threshold voltage of the driving TFT and the power line voltage, guaranteeing the uniformity of the current. Simulation results demonstrate that the relative current error rates are below 3.7% as the threshold voltage varies ±0.5 V and below 5.3% as the threshold voltage varies ±0.5 V and the power line voltage drops by 1 V; the programming time can be as short as only $12~\mu \text{s}$. [ABSTRACT FROM AUTHOR]

This paper presents a simple pixel structure that uses the voltage-programmed method to compensate for the electrical characteristic variations in low-temperature polycrystalline-silicon thin-film transistors and the current-resistance ( \(I\) – \(R\) ) voltage drop in the power line for active-matrix organic light-emitting diode displays. Based on the experimental results, the functionality of the pixel circuit can be operated correctly during each operation phase. Moreover, the pixel current exhibits high uniformity against the threshold voltage and mobility variations in the driving TFT. [ABSTRACT FROM AUTHOR]