SCANNING ELECTRON MICROSCOPE

PURPOSE:To make a screen easier to see, and to improve operability in selecting visual fields and focal points by displaying a fixed image without continuously scanning regions of low magnification for selecting visual fields. CONSTITUTION:The electron beam 2 emitted from an electron gun 1 is converged on a sample through a converging lens 3 and an objective lens 6. The electron beam 2 scans a sample 7 by means of a deflection coil 5 driven by a scanning signal generation circuit 18 and an amplification circuit 19, and an image signal such as secondary electron thus generated is detected by a detector 10, and an image signal is stoked in a memory 26 through an amplifier 11 via an A/D converter 24, and an image is displayed by a monitor 29. A low magnification image for selecting visual fields is displayed by adding a fixed image, for which the image data once stored in the memory is held and output, to a marker displaying signal generated on a marker displaying circuit 28, by means of an adder 31, and by superimposing a rectangular frame on the monitor 29. An image signal is taken in to a memory 27 by controlling the current of the deflection coil 5 or a visual field moving coil 4 and is output to a monitor 30, and a high magnification image is thus displayed.