Electron sources utilizing negative electron affinity photocathodes with ultra-small emission areas
US5684360A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Jul 10, 1995 |
| Grant date | Nov 4, 1997 |
| Priority date | — |
| Expiry date | Jul 10, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2201/3423
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An electron source includes a negative electron affinity photocathode on a light-transmissive substrate and a light beam generator for directing a light beam through the substrate at the photocathode for exciting electrons into the conduction band. The photocathode has at least one active area for emission of electrons with dimensions of less than about two micrometers. The electron source further includes electron optics for forming the electrons into an electron beam and a vacuum enclosure for maintaining the photocathode at high vacuum. In one embodiment, the active emission area of the photocathode is defined by the light beam that is incident on the photocathode. In another embodiment, the active emission area of the photocathode is predefined by surface modification of the photocathode. The source provides very high brightness from an ultra-small active emission area of the photocathode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.