Dynamic compensation of non-linear electron beam landing angle in variable axis lenses
US5285074A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 3, 1992 |
| Grant date | Feb 8, 1994 |
| Priority date | — |
| Expiry date | Jun 3, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/3175
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A dynamic correction arrangement for an electron beam projection/deflection system provides high order correction values for deflection in accordance with a correction equation. Particularly as applied to high accuracy telecentric deflection, the coefficients of terms of the correction equation may be determined by calibration for a small number of test points. Correction values may be stored in a look-up table or computed in real time by using a math co-processor in a processing pipeline. The correction provided corrects landing angle errors through the third order in telecentric projection/deflection systems such as systems utilizing variable axis immersion lenses.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.