Patent Number: 
Section: abstract

It is an object of the present invention to provide an projection imaging type electron microscope in which the imposition of restrictions on the design of the illumination electron optical system by the conditions of the projection electron optical system is alleviated, so that the degree of freedom in the design of the illumination electron optical system is increased. Generated electrons 6b (principal rays) emitted from the sample 5 parallel to the optical axis are focused by a cathode lens so that these electrons cross the optical axis 3 at one point. This point is the first crossover. The generated electrons 6b are oriented parallel to the optical axis by the cathode lens 4a, and are focused as an image at the position of the electromagnetic prism 2; these electrons pass through the stigmator 7, and are incident on the relay lens 8a. These electrons are again focused, and cross the optical axis 3 at one point. This position is the second crossover. An aperture diaphragm 11 is disposed in this second crossover position. As a result, the need to install an aperture diaphragm in the first crossover position is eliminated, so that design of the illumination electron optical system is facilitated.