Transmission electron microscope
The imaging principle of an electron microscope and an optical microscope is basically the same, except that the former uses an electron beam as a light source and an electromagnetic field as a lens. In addition, since the penetrating power of the electron beam is very weak, the specimen used for the electron microscope must be made into an ultra-thin section with a thickness of about 50 nm. This section needs to be made with an ultramicrotome. The electron microscope has a magnification of up to nearly one million times. It consists of five parts: the lighting system, the imaging system, the vacuum system, the recording system, and the power supply system. Electron guns, condensers, objective chambers, objectives, diffractive mirrors, intermediate mirrors, projection mirrors, screens and cameras in vacuum.