MAGNIFICATION DETERMINATION DEVICE USED IN ELECTRON MICROSCOPE

摘要

PURPOSE:To determine a wide range of magnifications by calculating them by using the signal representing the constant speed at which a part having an edge on which the sample is placed is moved and the speed at which an image of the edge moves on the projection screen. CONSTITUTION:Electron rays 1 are irradiated upon the thin plate 3 of a sample- pulling device 2, which consists of a fixed part 2a and a movable part 2b including the thin plate 3 having an edge (E), to produce an image of the thin plate 3 on a fluorescent plate 8 having two electron-ray holes 8a and 8b in the ends. Both the speed at which the thin plate 3 is moved by a driving circuit 4 and the signal produced by passing the signals of detectors 9a and 9b facing the holes 8a and 8b of the fluorescent plate 8 through an adder circuit 12, an and circuit 14 and a counter circuit 16 are used as the inputs to an arithmetic unit 17 to calculate the observation magnification which is then displayed on a display device 19. Accordingly, it is possible to easily determine magnification levels of different ranges simply by switching the speed of sample movement.