Scanning electron microscope with conversion means to produce a diffraction pattern

Claim 1

In a scanning electron microscope, means for producing conventional scanned images and alternately producing diffraction patterns of the scanned area on the specimen surface comprising: A. a column for housing the microscope; B. an electron gun at one end of the column for emitting an electron beam; C. A condenser lens system within said column for focusing the electron beam comprising at least two lenses; D. a field limiting baffle having an aperture therein arranged between two of said lenses; E. a specimen holder for positioning a specimen in the path of the electron beam focused by the condenser lens system; F. a scanning deflection means for causing the electron beam to scan over the specimen surface, said deflection means positioned between the electron gun and the baffle thereby limiting the field scanned; G. means for detecting backscattered electrons, secondary emissions and/or transmitted electrons and means synchronized with the scanning deflection means for displaying a conventional scanning microscope image; means for converting the microscope from a scanning to a diffraction mode comprising; H. means for focusing the electron beam on the back focal plane of the last condenser lens in the column and thereby causing a collimated electron beam to irradiate the same surface scanned; I. means on the side of the specimen opposite the electron gun for detecting the diffraction pattern; and, J. means for displaying the diffraction pattern.