Infrared intrusion detector
US4710629A · kind A · utility
16Cited by
4References
19Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 26, 1985 |
| Grant date | Dec 1, 1987 |
| Priority date | — |
| Expiry date | Dec 26, 2005 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S250/01
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
In an infrared intrusion detector which evaluates the body radiation of an intruder by means of a dual radiation sensor having two sensor elements arranged in a differential circuit for emitting an alarm signal, a functional supervision and detection of an attempt at sabotage, e.g., by covering or spraying the entrance window, are achieved by asymmetric irradiation of the two sensor elements through the entrance window by a radiation source. The asymmetry can be achieved by disposing the radiation source outside the plane of symmetry of the sensor elements or by an asymmetrically disposed auxiliary reflector.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.