Automatic exposure control
US4093376A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 1, 1976 |
| Grant date | Jun 6, 1978 |
| Priority date | — |
| Expiry date | Jun 1, 1996 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B27/80
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The disclosure relates to an automatic exposure control system for use in a document recorder of the type which makes a photographic reproduction of each of a series of documents and which has a document transport for feeding the documents along a predetermined path and an exposure station within the predetermined path including an exposure light source for illuminating each document as each document is presented to the exposure station to facilitate the photographing of the documents. The automatic exposure control system controls the illumination intensity of the exposure light source in response to the reflectivity of each document to assure proper exposure of each document. It includes a first light source arranged relative to the predetermined path in advanced relation to the exposure station relative to document travel for projecting light onto the documents, a first light sensitive element arranged relative to the predetermined path for receiving the light reflected from the documents originating from the first light source for providing a first control signal having a magnitude directly related to the intensity of the reflected light, a feedback arrangement coupled between …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.