| 摘要 |
<p>An appts. for limiting the electron beam of an electron-optical device, comprises a completely open region or regions and, in addition, a uniform and consistent material, in two completely different thicknesses the thinner region of which is adjacent to the aperture and constitutes its surround while the thicker region constitutes a stiffening rib or frame. Pref. the continuous, cohesive material is a heavy metal, more specifically. Used partic. as the object aperture plate of an electron microscope. As the condenser aperture plate of an electromicroscope.</p> |
