Intensity control for the imaging beam of a raster scanner
US4559546A · kind A · utility
7Cited by
5References
10Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Sep 4, 1984 |
| Grant date | Dec 17, 1985 |
| Priority date | — |
| Expiry date | Sep 4, 2004 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K15/1214
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A raster output scanner in which a twisted nematic liquid crystal is disposed in the path of the linearly polarized scanning beam incident on the scanner modulator to provide controlled rotation of the plane of polarization of the beam to maximize modulator diffraction efficiency and beam intensity, control over the crystal external electric field being either exercised manually or automatically, the latter through a feedback loop using a photodetector to monitor changes in beam intensity at the scanner photoreceptor. In an alternate embodiment, the liquid crystal is replaced by a magneto-optic cell.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.