Detector-array with mask warning
US6239698A · kind A · utility
7Cited by
1References
7Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jul 12, 1999 |
| Grant date | May 29, 2001 |
| Priority date | — |
| Expiry date | Jul 12, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B29/046
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
When an array of thermal detectors with appropriate read-out means is used as a sensor to detect events such as intruders or fire, it may be disabled accidentally or deliberately by placing a mask over the array to shield it from the scene. The act of placing a mask over the array induces a simultaneous transient signal from all of the detectors, or at least a majority of the detectors, and is followed by a period when those detectors give rise only background noise or clutter. The characteristics of these signals is used to generate a warning signal to indicate that the sensor has been disabled.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.