System for absorbing and or scattering superfluous radiation in an optical motion sensor
US6121876A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 24, 1998 |
| Grant date | Sep 19, 2000 |
| Priority date | — |
| Expiry date | Mar 24, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B13/193
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
An infrared intrusion sensing system comprises a compound lens having a plurality of lines of focus for focusing infrared radiation that enters the system onto a detector, and a window to allow infrared radiation to enter the system and then be focused onto the detector by a set of curvilinear-shaped mirrors. The detector is located near the focal point of the compound lens elements and curvilinear-shaped mirror elements. An enclosure surrounding the detector provides isolation from insect entry and constitutes an insect exclusion enclosure envelope. The enclosure envelope is a protective volume of space for the optical paths between the lens or window and the detector that prevents the entry of objects about 1 mm in diameter or larger which could interfere with the optical paths. Pigmenting, texturing, and/or contouring the insect exclusion enclosure surrounding the detector is provided for the purpose of absorbing and/or scattering superfluous radiation that is not focused on the detector, thereby minimizing false alarms and providing improved operating performance by the infrared intrusion sensing system. An alternate embodiment provides an insert for the insect exclusion enclos…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.