Method and apparatus for the detection of defective light transmitters and/or receivers of a light grid for detecting objects in a surveillance area
US5583334A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 14, 1994 |
| Grant date | Dec 10, 1996 |
| Priority date | — |
| Expiry date | Nov 14, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B13/183
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A light grid consists of a row (13) of adjacent light transmitters (11.sub.i) and adjacent light receivers (12.sub.i) arranged at a distance opposite to the latter. The light transmitters (11.sub.i) and the associated light receivers (12.sub.i) are individually activated cyclically one after the other. A determination is made at each light receiver (12.sub.i) whether a received light signal is present or not on activation of the associated light transmitter (11.sub.i). By considering, during the evaluation, the light receivers (12.sub.i-1, 12.sub.i+1) adjacent to the associated light receiver (12.sub.i) and the light transmitters (11.sub.i+1, 11.sub.i-1) adjacent to the associated light transmitter (11.sub.i), a differentiation is made between an obstacle introduced into the protective field (26) and a defect light transmitter (11.sub.i) and/or light receiver (12.sub.i).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.