Electron microscope
US4434367A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 28, 1981 |
| Grant date | Feb 28, 1984 |
| Priority date | — |
| Expiry date | Jul 28, 2001 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J37/26
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An electron microscope comprises an objective lens, at least an intermediate lens and a projector lens arrayed in this order on an optical axis. A movable aperture element is disposed between the objective lens and the intermediate lens whose disposition and magnetic excitation are so selected that electron beam diverging from a crossover produced at a back focal plane of the objective lens is focused on a plane of the movable aperture element. In the case of an electron microscope comprising an objective lens, an objective aperture element, a selected area aperture element, at least an intermediate lens and a projector lens arrayed in this order along an optical axis, an additional lens is disposed between the objective aperture element and the selected area aperture element. Disposition and magnetic excitation of the additional lens are so selected that electron beam diverging from a crossover produced at a back focal plane of the objective lens is focused at a plane of the selected area aperture element. In both electron microscopes, divergence angle of the electron beam scattered by a specimen is restricted by the movable aperture element or the selected area aperture element.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.