Pyroelectric detectors
US4284888A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 18, 1979 |
| Grant date | Aug 18, 1981 |
| Priority date | — |
| Expiry date | Oct 18, 1999 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S250/01
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
An intruder detector consists of an element of pyroelectric material having three defined regions; two being active to infra-red radiation and one being relatively inactive to infra-red radiation. The inactive region and one of the active regions are connected together in parallel and the other active region is connected in series with these two. The arrangement has full cancellation of environment effects while being partially unbalanced for infra-red detection so that isolated areas of infra-red radiation (such as an intruder) can be detected at long and short ranges. The element is used with a concave mirror for increased zonal coverage. Each of the regions of pyroelectric material has a substantially constant thickness and all of the three regions have the same thickness.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.