Photosensitive switch with circuit for indicating malfunction
US5144286A · kind A · utility
2Cited by
8References
6Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Aug 6, 1990 |
| Grant date | Sep 1, 1992 |
| Priority date | — |
| Expiry date | Aug 6, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V8/14
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An alarm for a photosensitive detector used for detecting registration marks on a web or the like measures the voltage levels of an intensity signal derived from the registration marks and the background as it moves past the photosensitive switch. Pulses that are sufficient to operate the photosensitive switch but are below a level deemed to indicate reliable operation are counted and set an alarm if a predetermined number occur without an intervening pulse of a higher amount.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.