Magnetic electron lens
US4219732A · kind A · utility
14Cited by
4References
5Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Mar 28, 1979 |
| Grant date | Aug 26, 1980 |
| Priority date | — |
| Expiry date | Mar 28, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J37/141
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
In a scanning electron microscope, an objective lens field is generated between a pair of deflecting coils and a specimen by an objective lens having upper and lower magnetic pole pieces. A supplemental magnetic pole piece is installed between said upper and lower magnetic pole pieces so that the half width of the objective lens axial magnetic field distribution is increased and the principal plane of the objective lens is positioned near the lower pole piece. By so doing, the spherical aberration coefficient of the objective lens is reduced and a high resolution scanning image is obtained.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.