Low Aberration field emission electron gun
US5196707A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 4, 1991 |
| Grant date | Mar 23, 1993 |
| Priority date | — |
| Expiry date | Mar 4, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/06316
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A field emission source is used in conjunction with a three element asymmetric lens system to provide an electron gun having greater magnitude beam currents focused on a smaller spot size than has been previously possible for intermediate energy beams. The three element asymmetric lens system has a lower spherical aberration than prior art electrostatic guns and a very low chromatic aberration coefficient, enabling precise focusing of beams with large currents and energy spreads. The electron gun produces high current densities in beam focused on small spot areas, despite the relatively large acceptance angle and energy spread of the source beams.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.