Objective lens
US8178849B2 · kind B2 · utility
1Cited by
14References
32Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Sep 1, 2009 |
| Grant date | May 15, 2012 |
| Priority date | — |
| Expiry date | Feb 17, 2030 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J37/1471
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An objective lens for focussing charged particles includes a magnetic lens and an electrostatic lens whose components are displaceable relative to each other. The bore of the outer pole piece of the magnetic lens exhibits a diameter Da which is larger than a diameter Di of the bore of the inner pole piece of the magnetic lens. The following relationship is satisfied: 1.5·Di≦Da≦3·Di. The lower end of the inner pole piece is disposed in a distance of at least 2 mm offset from the inner end of the outer pole piece in a direction of the optical axis.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.