Microscopes.

In order to study the fine structure of metallic materials, three different designs of microscopes are used: The specimen is illuminated, and an appropriate system of lenses projects its image (light-optical microscope, transmission electron microscope). The system of lenses is used to produce a fine point, with which the surface of the specimen is scanned. The image is then shown on a television screen (electron scan microscope, microprobe. By means of straight rays, i. e. without lenses, a small sphere is projected on a large sphere (electron field emission microscope, ion field microscope, x-ray microscope).