| 摘要 |
PURPOSE:To enlarge the deflection angle of incident beam thus to enable highly accurate focusing by varying the incident angle of electron beam to be projected onto a sample and focusing through a thin hole in an iris board for objective lens having plural thin holes onto a fluorescent plate. CONSTITUTION:The electron beam 3 from an electron gun 2 in a transmission electron microscope is deflected through a deflection coil 4 in a warpler device by the angle theta and projected onto a sample 6. The transmitted electron beam is passed through an objective lens 7 and a thin hole B1 in an iris board 11 having a central hole A and plural thin holes B1, B2 at the opposite sides to be focused onto a fluorescent plate 9. When varying the incident angle of electron beam 3 by the angle theta to the opposite direction, the electron beam is passed through the thin hole B2 of the iris board 11 to be focused. Since the image can be observed under the condition where the incident angle of the electron beam against the sample 6 is considerably varied, motion of image can be increased resulting in highly accurate focusing.
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