Phosphor coated waveguide for efficient collection of electron-generated photons
US6775452B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | May 18, 2001 |
| Grant date | Aug 10, 2004 |
| Priority date | — |
| Expiry date | Aug 16, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/2443
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A phosphor coated waveguide for efficient collection and detection of back-scattered electrons in an electron beam apparatus such as a scanning electron microscope is disclosed. The waveguide for directing photons to an optical detector generally comprises a first waveguide portion having opposing first and second faces defining a beveled hole therebetween to allow an electron beam to pass therethrough, the beveled hole decreasing in cross-sectional size from the first to the second face. A phosphor coating on the second face around the beveled hole converts the back-scattered electrons to photons. The first waveguide portion may include angled faces at an end further from the optical detector. A surface defined by the beveled hole and/or the angled faces may have a reflective coating. The waveguide may also include a second waveguide portion that adjoins and flares out relative to the first waveguide portion to further increase waveguide efficiency.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.