Process for determining the location of edges and photoelectronic scanning device for scanning edges
US5021674A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 16, 1990 |
| Grant date | Jun 4, 1991 |
| Priority date | — |
| Expiry date | Jan 16, 2010 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB65H2553/412
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A process and device for determining the location of at least one edge of a moving web within a measurement zone and in which a linear array of liquid crystal light modulators is interposed between a light source and a light receiver extending transversely to the edge along a scanning zone while a controller successively activates the light modulators to scan a transparent surface zone along the measurement zone. The point at which light is last received (because of obstruction by the edge) or the first received in a pass (because of lack of obstruction by the edge) at the receiver from the source through the scanning transparent zone is used as the measure of the location of the edge.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.