Lens system for document scanning
US4266252A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 12, 1979 |
| Grant date | May 5, 1981 |
| Priority date | — |
| Expiry date | Sep 12, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/113
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A lens system for scanning a document positioned on a flat support. The lens system operates in cooperation with apparatus which scans a beam of illuminating light across the document and a scanning mirror, which directs reflected light from the illuminated document in a direction toward an array of photodetectors. The lens system is positioned between the scanning mirror and the photodetector array and includes a movable doublet lens and fixed doublet lens. The movable doublet lens collimates the light through the lens system, while the fixed doublet lens focuses an image of the scanned document portion upon the face of a photodetector array. A set of 6 correcting lenses are arranged symmetrically with respect to a plane of symmetry in a position between the two doublet lenses. A barrel cam and a follower arrangement is provided for moving the movable doublet lens in synchronism with the image scanning mirror, so that optical field flattening is achieved.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.