IMAGE DISTORTION-FREE, IMAGE ROTATION-FREE ELECTRON MICROSCOPE

摘要

A transmission electron microscope comprises an imaging electron lens system constituted in at least five stages by an objective lens, a group of intermediate lenses and a group of projector lenses to which excitation currents are applied with alternately different polarities. Lens current control means is provided for controlling the excitation currents in such a manner that the lenses belonging to the intermediate lens group and the projector lens group, respectively, serve as reduction lens when the microscope is operated in a predetermined range of low magnifications, while all the electron lenses serve as magnifying lenses in a predetermined range of high magnitudes. When the magnification is changed over, the lens current control means regulates the excitation currents in such a manner that the difference between the excitation currents supplied to the intermediate lens group and the projector lens group, respectively, is maintained substantially constant.