Electron beam projection apparatus
US5319198A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 30, 1992 |
| Grant date | Jun 7, 1994 |
| Priority date | — |
| Expiry date | Nov 30, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/188
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An electron beam projection apparatus including electron injection unit for irradiating an object with an electron beam. The electron injection unit includes a substrate, a cathode formed on the substrate for emitting the electrons, a control electrode formed on the substrate via an insulation layer in a manner enclosing the cathode for accelerating the electrons, and an anode formed on the control electrode via an insulation layer in a manner enclosing the cathode for converging the electron beam. The electron beam projection apparatus further including detecting unit formed on the anode via an insulation layer for detecting secondary electrons emitted from the object irradiated with the electron beam and differential pumping unit for producing a low vacuum condition in an space where the electron beam travels from the microscopic electron injection unit to the object. By maintaining a low vacuum condition, in the area where the electron beam is projected and detected, by using simple structural differential pumping unit, the detection accuracy can be achieved since the secondary electrons are amplified in the low vacuum area by the ionization of gas molecules.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.