Amorphous selenium (a-Se) is a direct flat detector structure, which is mainly composed of collector matrix, selenium layer, dielectric layer, top electrode and protective layer. The collector matrix is composed of thin film transistors (TFTs) arranged in the array. Amorphous selenium semiconductor materials are deposited on the top of the thin film transistor array by vacuum evaporation to produce a thin film with a thickness of about 0.5mm and a square of 38 mm × 45 mm. It is sensitive to X-ray and has a high image resolution ability.
When X-ray incident occurs, because of the electric field formed by the high voltage power supply on the surface of amorphous selenium, they can only pass through the insulation layer, X-ray semiconductor and electronic sealing layer vertically along the electric field direction to reach the amorphous selenium, and there will be no transverse deviation and light scattering. The amorphous selenium array directly transforms X-ray into electrical signal, memory in storage capacitor, pulse control gate circuit makes thin film transistor turn on, and the charge stored in storage capacitor is sent to charge amplifier output, and photoelectric signal is converted, and then converted by digital converter to form digital image input computer, and the image is restored to monitor by computer and then medical treatment is performed The direct diagnosis was performed by the observation monitor.