Abstract: A flat panel detector for radiation imaging includes an array of pixels arranged in rows and columns. Gate lines interconnect the pixels of each row while source lines interconnect the pixels of each column. A radiation transducer is disposed over the pixel array. Each pixel includes a TFT switch having its gate electrode connected to a gate line and its source electrode connected to a terminal that is connectable to ground. The drain electrode of each TFT switch is connected to the pixel electrode of the pixel. The pixel electrode and a bottom electrode connected to a source line constitute a storage capacitor. When the TFT switch is biased and the pixel electrode is positively charged, the pixel electrode discharges through the TFT switch and onto the grounded terminal. This results in the release of negative charge held by the bottom electrode onto the source line, which is sensed by a charge amplifier connected to the source line.

Abstract: A method and apparatus of operating a dual gate TFT electromagnetic radiation imaging device wherein the electrical conditions on each pixel are compared after exposure to radiation and during measurement. The pixel charge electrode is preset to a predetermined voltage level prior to radiation exposure so that the pixel may be operated beyond its linear operating range.