Electron beam apparatus comprising an anode which is included in the cathode/Wehnelt unit
US4798957A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 7, 1987 |
| Grant date | Jan 17, 1989 |
| Priority date | — |
| Expiry date | Dec 7, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J3/027
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A cathode (32), a Wehnelt cylinder (2, 36) and an anode (3, 51) are accommodated in an integrated unit in an electron beam apparatus. Extremely accurate positioning of a Wehnelt bore and an anode bore with respect to one another can be achieved in such an assembled unit which is mounted in the apparatus so as to be removable as one unit. An exactly defined distance between the Wehnelt cylinder and the anode can also be adjusted. As a result of the exact mutual positioning, the anode bore can be chosen to be so small that it can also act as a beam aperture so that a smaller electron-optical object as well as a substantial reduction of the mutual electron interaction in the beam is achieved.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.