Image reading apparatus
US5687008A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 11, 1996 |
| Grant date | Nov 11, 1997 |
| Priority date | — |
| Expiry date | Jan 11, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N2201/0418
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A drum scanning type image reading apparatus includes an illumination optical system and an imaging optical system. The illumination optical system is an optical system for irradiating light upon an original. A variable aperture stop is disposed at a conjugate position with the original. In the imaging optical system, a pick-up lens focuses an image of an image reading region of the original on an image focusing surface, and photomultiplier tubes read light passing through one of holes which are formed in a main aperture plate which is disposed on the image focusing surface. To change an image reading resolution in the image reading apparatus, the image reading region and an illumination region are changed by changing the aperture size of the main aperture plate and the size of the variable aperture stop.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.