| 摘要 |
<p>A technique for focusing an electron microscope independently of the sample characteristics and correcting the astigmatism. The electron microscope has first computing means for computing the actual measurement quotient of the mutual division of FFT images formed at a first focal point and a second focal point with a known focus deviation and second computing means for determining a first theoretical quotient of mutual division of two transfer functions defined by substituting the two focal positions in an image transfer function with a spatial frequency plane, determine a second theoretical quotient correlated with the first actual measurement quotient with reference to quotient data created as a function of the focal point and the spatial frequency and stored, and determine that the focal point corresponding to the second theoretical quotient is the first focal point.</p> |
