Passive infrared intrusion detector and its use

Details Passive infrared intrusion detector and its use Passive infrared intrusion detector and its use

1996-11-01

1999-08-24

Hofsass, Jeffery A.

Communications: electrical

Condition responsive indicating system

Specific condition

340567, 250DIG1, G08B 1300

Patent

active

059429763

ABSTRACT:
A passive infrared intrusion detector for the detection of infrared body radiation includes a sabotage detector, in particular for detecting spraying of the entrance window of the intrusion detector. The sabotage detector includes a light source, a corresponding light sensor, and an optical diffraction grating structure on the outside of the entrance window. The light source and the light sensor can be on the same or on opposite sides of the entrance window. By first- or higher-order diffraction, light from the light source is focused onto the sensor, and a resulting electrical signal from the sensor is evaluated by an evaluation circuit. In case of sabotage, the focusing effect of the optical diffraction grating structure vanishes, so that the light intensity at the detector is reduced. The drop in light intensity triggers a sabotage alarm signal.

REFERENCES:
patent: 4242669 (1980-12-01), Crick
patent: 4375034 (1983-02-01), Guscott
patent: 4710629 (1987-12-01), Muller et al.
patent: 4752768 (1988-06-01), Steers et al.
patent: 5424718 (1995-06-01), Muller et al.
patent: 5489892 (1996-02-01), Imuro et al.
patent: 5491467 (1996-02-01), Tracy et al.
patent: 5499016 (1996-03-01), Pantus

Affiliated with

Also associated with

Rating

Passive infrared intrusion detector and its use does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Passive infrared intrusion detector and its use, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Passive infrared intrusion detector and its use will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-470548