Arrangement to prevent false alarms by passive infrared-movement signallers

摘要

In an infrared motion detector sensitivity to glass penetrating electromagnetic radiation, it is proposed to reduce to bonding the optical filter (9) located in front of the input of the infrared detector (2) having a heat sink in the form of a solid metal pot (6). Changes in the optical filter (9) of absorbed radiation are either collected in the heat sink or at least slowed down in the natural heat radiation of the optical filter (9) and no longer fall within the range of the motion characteristic change. To FIG. 1.