| 摘要 |
PURPOSE:To obtain a high-quality image with a low multiplying factor and a high visual field by making the non-axial aberration and the axial aberration of a transmission-type electron microscope small by installing a setting lens between an objective lens and a visual-field limiting stop, and focusing an electron beam on the visual-field limiting stop by means of the objective lens and the setting lens. CONSTITUTION:A transmission-type electron microscope has an objective lens 3, an intermediate lens 5 installed in back of the lens 3, an imaging lens 7, and a visual-field limiting stop 4 located between the lenses 3 and 5. A setting lens 10 is provided between the lens 3 and the stop 4. In addition, a focusing lens 1 is provided in front of the lens 3, and an electron beam is irradiated on a sample 2 after being focused by the lens 1. The above lens 3 is relatively weakly excited, and the lens 10 is excited to a given degree so as to make an electron beam 8 transmitted by the sample 2 to be focused on the stop 4. Consequently, the contrast of an observed image is increased by regulating the opening angles of electron rays scattered from the sample 2 by controlling the stop 4. |
