The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 16, 1991
Filed:
Feb. 27, 1990
Kimio Kanda, Katsuta, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A beam of, e.g. an electron microscope, is focussed on a specimen and secondary electrons generated thereby are detected and analyzed to generate an output signal. That output signal is investigated for one magnification or scanning time of the beam over a range of foci to determine the optimum output value for that one magnification. This investigation is repeated for other magnifications to generate a series of optimum output values. The optimum of that series is then determined, and the electron microscope may then be operated for that specimen at the focus corresponding to the optimum of the series of optimum values. In this way, automatic focussing is provided which permits the optimum focus to be determined in dependence on the specimen.