Chuanli Leng

An a-IGZO TFT pixel circuit for AMOLED with simultaneous V T compensation

In this paper, a four a-IGZO TFTs based pixel circuit with simultaneous VT compensation function for AMOLED is proposed. The proposed circuit can not only simplify the peripheral circuits of the panel, but also compensate for both positive and negative VT shift with a charging VT-generation method. Simulation results show that the current changes only by 18.9% and 3.9% when ΔVT is -3 V and 2 V, respectively. Furthermore, by applying the grouping driving scheme, the OLED lighting time can be largely increased which manifests superiority when applied to high resolution or high frame rate displays.

An Accurate and Fast Current-Biased Voltage-Programmed AMOLED Pixel Circuit With OLED Biased in AC Mode

A current-biased voltage-programmed (CBVP) pixel circuit for active-matrix organic light-emitting diode (AMOLED) displays is proposed. The pixel circuit can not only ensure an accurate and fast compensation for the threshold voltage variation and degeneration of the driving TFT and the OLED, but also provide the OLED with a negative bias during the programming period. The negative bias prevents the OLED from a possible light emitting during the programming period and potentially suppresses the degradation of the OLED.

An IGZO TFT based in-cell capacitance touch sensor

An in-cell active matrix capacitive touch sensor using IGZO TFT is proposed in this paper. The sensor does not need touch deformation, complicated detection mechanisms or extra components. In the sensor, touching events are identified as capacitive coupling between internal detection electrodes and touch objects. Then the coupling can be converted to voltage signal and amplified. TFT sizes are decreased for the high mobility and good uniformity of IGZO, which result in a significantly improved accuracy. A capacitance with the order of 1 fF caused by the coupling could be detected and converted to an adequate output voltage signal.