Correlated double sampling circuit integrated on glass used for active pixel sensing array

In recent years, promoting the sensing accuracy of the image pixel sensor has become a hot issue. For voltage type active pixel sensor (V-APS), the readout voltage, as well as the sensing signal, will be affected by the thin film transistors (TFTs) characteristic variation, especially the shift in threshold voltage (Vth). In this paper, we introduce a novel correlated double sampling (CDS) circuit, which can be implemented on glass by only using TFTs and capacitors. Thus, the readout voltage variation due to the threshold voltage shift under same light intensity illumination can be eliminated.