Swath scanning system using an optical imager
US6088134A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 17, 1996 |
| Grant date | Jul 11, 2000 |
| Priority date | — |
| Expiry date | Jun 17, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N2201/02483
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The invention is a system for scanning a document. A light source illuminates the document; an imager receives light from the document and directs it toward a detector array which produces a corresponding array of electrical signals. The imager has several optical properties that are useful either individually or in combination. The imager is telecentric and thereby ensures that image size and magnification are insensitive to object displacement along the optical axis and image brightness is uniform independent of object off-axis distance. An aspheric element within the imager balances focus variation within the depth of field with spherical aberration and thereby provides nearly uniform image resolution. A diffraction pattern, carried by the imager, corrects for spectral dispersion which occurs when light passes from air into a refractive material. An imager with a reflecting surface provides a system that is subject to little or no chromatic aberration. A solid imager with multiple internal reflecting surfaces in optical series, configured to include the previously mentioned optical properties, also provides for highly stable alignment of reflecting surfaces.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.