Composite concentric-gap magnetic lens and deflector with conical pole pieces
US5729022A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 26, 1996 |
| Grant date | Mar 17, 1998 |
| Priority date | — |
| Expiry date | Sep 26, 2016 |
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.