Pyrodetector
US4404468A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 27, 1981 |
| Grant date | Sep 13, 1983 |
| Priority date | — |
| Expiry date | Jul 27, 2001 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S250/01
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A pyrodetector is disclosed which has a sharply limited directional range of detection sensitivity for the detection of a body entering into its directional range at a distance from the detector, the body having a temperature which is different from that of its environment. A concave mirror for focusing thermal radiation emanating from the body is provided and a pyroelectric sensor positioned at a focus of the mirror is also provided and formed as a flat body consisting of an electrically non-conductive material and with a pair of electrodes. A cover transmissive to the incident thermal radiation is provided for protecting the sensor element against damage and air drafts. At least one further sensor element similar to the first sensor element and with essentially the same heating time constant is also provided and arranged adjacent to the first sensor element but beyond the mirror focus. The electrode pairs of all the sensor elements are connected to an electrical evaluation circuit which forms a difference between an output signal of the first and further sensor elements. The pairs of electrodes are each terminated with an impedance such that a time constant K of a decay time of t…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.