Adjustable diaphragm, diaphragm conversion system and electron microscope

The invention relates to the technical field of microscopic imaging and particularly relates to an adjustable diaphragm, a diaphragm conversion system and an electron microscope. The adjustable diaphragm comprises an imaging unit, a control unit, a driving unit, a servo motor and an adjustable diaphragm, wherein the adjustable diaphragm comprises two rotating cores, the rotating cores are in mirror image correspondence with each other, and rotating shafts are arranged on the rotating cores. The adjustable diaphragm is advantaged in that the diaphragm automatic conversion device is additionally arranged in the electron microscope, and meanwhile, the structure and the transmission mode of a traditional diaphragm are changed, so diaphragm conversion and imaging can be synchronized, and a series of images obtained under the action of different diaphragms can be automatically obtained; the gear structure disclosed by the invention can completely resist electrons at a slit position between the two rotating cores, s