Magnetic lens and deflector with inner and outer pole pieces with conical inner pole piece
US6002135A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 14, 1998 |
| Grant date | Dec 14, 1999 |
| Priority date | — |
| Expiry date | Jan 14, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J37/141
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A composite magnetic lens and deflector for particle beam optical systems has a concentric gap and concentric conical lower pole pieces arranged to allow more accurate magnetic deflection. The flux generated by a solenoidal lens coil is shared by magnetically soft inner and higher saturation flux outer pole pieces to minimize saturation effects, while the flux generated by internal deflection coils is confined to magnetically soft inner pole pieces that minimize flux leakage and associated eddy current settling effects. Shielding rings further contain leakage flux. The inner magnetic circuit is mounted and adhesively bonded to radial flexures to minimize thermal expansion drifts.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.