Direct imaging monochromatic electron microscope
US4882487A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 8, 1988 |
| Grant date | Nov 21, 1989 |
| Priority date | — |
| Expiry date | Nov 8, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J37/141
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A direct-imaging, monochromatic electron microscope includes an objective lens for collecting a substantial portion of emitted electrons from an area across a sample surface, and focusing the electrons through an image plane. A collimating lens for collimating the electrons into beams is located at its focal distance from the image plane. An energy filter with an entrance aperture is receptive of the beams to transit monochromatic beams, and a transfer lens is receptive of the monochromatic beams for refocusing the same through a projection lens to effect an image of the plurality of spots in a projection plane. The objective lens is formed of a magnetic toroidal coil having a central hole therein with a dish-shaped magnetically permeable member cupped coaxially over the toroidal coil. The permeable member has a neck portion protruding through the central hole. The sample surface is interposed proximate the objective lens between the objective lens and the energy filter. The entrance aperture is positioned from the transfer lens by approximately a distance optically conjugate to the distance between the objective lens and the collimating lens.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.