Low-cost PIR scanning mechanism
US7875853B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jul 23, 2007 |
| Grant date | Jan 25, 2011 |
| Priority date | — |
| Expiry date | Oct 19, 2029 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B13/193
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A passive infrared sensor (PIR) for detecting infrared radiation which includes a lens positioned in a sensor housing, and a pyroelectric element electrically connected to a circuit board within a filter housing positioned in the sensor housing. A microprocessor is electrically connected to a main circuit board and controls a liquid crystal display (LCD) attached to the sensor housing. The lens overlaps the LCD. The LCD has LCD regions corresponding to lens regions of the lens. Using the microprocessor, the LCD regions selectively prevent radiation energy from passing to the pyroelectric element, and the LCD regions selectively allow radiation energy to pass to the pyroelectric element. A signaling device communicates an alarm signal indicating when radiation energy within a specified wavelength band reaches the pyroelectric element.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.