Apparatus for detecting x-ray and operating method thereof

PURPOSE: An X-ray image photographing apparatus and a driving method thereof are provided to prevent the degradation phenomenon generating by the line unit, and to obtain high quality image data. CONSTITUTION: An X-ray image photographing apparatus(20) comprises a scintillator panel(22), an image extracting unit(23), a gate driver(24), an automatic exposure request signal generator(30), and a controller(27). The scintillator panel converts X-rays radiated from an X-ray generator(10) into visible light. The image extracting unit includes plural pixels arranged in a matrix form, and charges the electric charge to the pixels by the quantity of the visible light. The gate driver selects a specific line from the image extracting unit, and applies a driving signal to the selected line. The automatic exposure request signal generator generates an automatic exposure request signal as a trigger signal for the initiation of the X-ray radiation. The controller controls the exposure location by the driving signal.