Projection lens assembly for planar electron source
US5134337A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 5, 1991 |
| Grant date | Jul 28, 1992 |
| Priority date | — |
| Expiry date | Jul 5, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J29/023
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A projection lens assembly (10) projects onto a display screen (38) electrons emitted from an output side (86) of an electron multiplier such as, for example, a microchannel plate (70). The projection lens assembly includes a dome-shaped mesh element (16) that is concave as viewed from the display screen. The mesh element is positioned between the microchannel plate and a filter element (20) having a beam-limiting aperture (22). The mesh element is of an aspherical shape that allows the projection lens assembly to project the electrons toward the display screen with substantially no spherical aberration, thereby forming near the beam-limiting aperture an electron beam crossover of small diameter. The beam-limiting aperture is formed with a relatively small diameter that allows the filter element to block electrons of energies outside a preselected range of energy values, thereby reducing chromatic aberration in the image formed on the display screen.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.