Apparatus with permanent magnetic lenses
US7064325B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 21, 2005 |
| Grant date | Jun 20, 2006 |
| Priority date | — |
| Expiry date | Apr 21, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J37/143
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The invention describes a particle-optical apparatus arranged to focus a beam (1) of electrically charged particles with the aid of two particle-optical lens systems (10, 20). The lens action is achieved by magnetic fields, which fields are generated by permanent-magnetic materials (13, 23). In contrast to magnetic lenses equipped with a coil, it is not easy in the case of lenses equipped with permanent-magnetic material to alter the focusing magnetic field with the aim of altering the optical power. In an apparatus according to the invention, the optical power of the lens systems is altered by altering the energy with which the beam (1) traverses the lens systems (10, 20). This can easily happen by altering the voltage of electrical power supplies (14, 24).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.