DETECTION SUBSTRATE AND MANUFACTURING METHOD THEREFOR, AND FLAT PANEL DETECTOR

The embodiments of the present disclosure provide a detection substrate, a preparation method thereof and a flat panel detector. An orthographic projection of a first electrode on the base substrate is set to be at least partially overlapped with an orthographic projection of an active layer of a thin film transistor on the base substrate, a first protruding part is arranged on a side, close to a corresponding data line, of the first electrode, an orthographic projection of the first protruding part on the base substrate is located between the orthographic projection of the active layer on the base substrate and an orthographic projection of the data line on the base substrate, thereby preventing hydrogen from diffusing to the active layer in the subsequent process of manufacturing the photoelectric conversion structure, effectively improving the stability of the thin film transistor, and improving the performance of the flat panel detector.