A concise pixel circuit with interleaved Emit signals is proposed for active matrix organic light-emitting diode (AMOLED) displays, on the basis of low-temperature polycrystalline silicon oxide (LTPO) TFTs. The oxide TFT can be re-used for both initialization and threshold voltage extraction periods, using interleaved Emit signals of adjacent lines with overlapped waveforms. The proposed pixel circuit consists of 1 oxide TFT and 5 p-type LTPS TFTs, while only 2~3 types of line-by-line scanning driving signals, i.e. the Emit signal and the Scan signal, are required. Implementation of the proposed pixel circuit showsthat the occupation can be reduced to 40 μm × 56.7 μm.Furthermore, optimization of the pixel circuit shows the emission current error is less than 2.3% with threshold voltage variation of ± 0.5 V, while refresh rate from 1 to 120 Hz can achieved.

In this paper, pixel circuit design method using low‐temperature poly‐silicon and oxides (LTPO) thin film transistors (TFTs) for active‐matrix organic light‐emitting diode (AMOLED) are derived in detail. Through calculation and SPICE simulation of a typical 7TFT‐1C LTPO pixel circuit, the optimum value for the capacitor is selected as 0.1 pF for accurate VTH compensation and high resolution above 490 pixels per inch (PPI). Moreover, to reduce the relative current error rate to 3 %, the maximum allowable threshold voltage shift is limited within −0.98 V and 0.44 V for IGZO TFT, and within −0.3 V to 0.31 V for the driving TFT (LTPS). This research provides guidelines for AMOLED display development using LTPO TFTs.

A two‐mode pulse width modulation (PWM) pixel circuit is proposed for Micro‐LED display. The proposed driving method divides the consecutive 8 sub‐frames (256 gray levels) into low‐bit and high‐bit subframes, which are respectively driven by simultaneous emission (SE) and progressive emission (PE) modes. Compared with the traditional PWM driving scheme, the proposed one shows an increased effective luminous time ratio by 40% for a frame rate of 120Hz, which benefits higher power conversion efficiency. There are only 5 dual‐gate metal‐oxide transistors for the pixel circuit, while a source‐follower structure is adopted to extract the threshold‐voltage shift(ΔVth). Simulation results demonstrate that the current error rates can be reduced to 2% with ΔVth of ± 1 V for various grayscales.

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Dynamic X‐ray detecting for large area medical imaging requires high‐gain and stable Active Pixel Sensor (APS) circuit integrated with Thin Film Transistors (TFTs). In this paper, the APS circuit using oxide TFTs is studied based on the small‐signal model, and the charge gain and effects of threshold voltage shift (ΔVth) are investigated. Detailed SPICE simulations show the charge gain of the APS circuit of the oxide TFTs is 234 × of that of the conventional a‐Si:H TFT PPS circuit.