Security sensor having disturbance detecting capability
US6469625B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Feb 6, 2001 |
| Grant date | Oct 22, 2002 |
| Priority date | — |
| Expiry date | Feb 6, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B29/046
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A security sensor 1 having a disturbance detecting capability capable of detecting the presence of an obstacle 8 purposefully applied to the sensor 1 in an attempt to fool or tamper the sensor 1 includes a carrier body A having an infrared sensor element 4, an incident side enclosure 5, such as a lens defining a detection area B, mounted on the carrier body A, a light projecting element 11 for projecting a disturbance detecting beam L1 from inside of the incident side enclosure 5 towards the incident side enclosure 5, a light receiving element 12 for receiving the disturbance detecting beam L1 reflected from the incident side enclosure 5, and a detecting circuit 15 for detecting a presence or absence of the obstacle 8 on the incident side enclosure 5, based on an amount of light received by the light receiving element 12. A multiplicity of projections 7 are formed on an outer surface of the incident side enclosure 5 so as to define a multiplicity of gaps between the obstacle 8 and the outer surface of the incident side enclosure 5, when the obstacle 8 is applied to the outer surface of the incident side enclosure 5.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.