Combined electrostatic objective and emission lens
US4551599A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 22, 1983 |
| Grant date | Nov 5, 1985 |
| Priority date | — |
| Expiry date | Aug 22, 2003 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J37/12
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A combined objective and emission lens for a microbeam probe is described which is suitable for primary and secondary particles of the same charge sign, by which lens a bundle of primary rays of comparatively high energy can be focused on a very small spot of a plane sample surface and the secondary particles emitted by this spot can be collected into a collimated bundle of secondary rays which leaves the combined lens in a direction substantially opposite to the bundle of primary rays. In the present combined lens, the field strength between the sample surface and the lens electrode most closely adjacent to it is very high, in contrast to the known combined objective and emission lenses, so that a small emissivity of the secondary beam with a small diameter at the same time of the primary beam spot and an effective collection and collimation of the secondary particles are ensured. Certain embodiments can be changed over optionally to operation with primary and secondary particles of the same or opposite polarity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.