Apparatus for controlling light distribution in line scan optical imaging systems
US4547813A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 27, 1984 |
| Grant date | Oct 15, 1985 |
| Priority date | — |
| Expiry date | Jan 27, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/0303
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Disclosed is a linear strip mask for controlling image plane light level distribution in line scan optical imaging systems. The mask is fabricated photographically on a strip of emulsion coated mylar. The photographic image which is recorded on the mylar strip is a pattern of alternating black and clear sections, the pattern of black sections chosen to modify the non-uniform light pattern output by the system's illumination source to obtain uniform image plane illumination. Also disclosed is a line scan optical imaging system utilizing strip masks to compensate for the non-uniform light output along the length of two fluorescent tubes which illuminate the document scan line and the cos.sup.4 drop-off of the imaging system's lens. Light reflected off the document scan line is transmitted via a four bounce folded mirror system and is received by the lens system. Behind the lens system is positioned a multielement photoelectric sensor for converting light reflected from each unit area of the document line being scanned into electrical signals.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.