JPS57161626A - Infrared detector - Google Patents

Abstract

PURPOSE:To provide an infrared detector which performs an accurate and high- reliable detection, by detecting enterance of a human being through integrating of reverse polar outputs from two infrared detectig elements for collecting infrared rays from a human body at a time lag. CONSTITUTION:A parabolic reflector 1 collects infrared rays from a human body entering in a movig direction P, collecting elements 3 and 2, located in parallel to a direction P, collect them at a time lag, and elements mutually generate reverse polar collecting signals. The collecting signals are shaped into a homopolar pulse by a wave form shaping circuit 8 of a signal processing unit 13, and if they are produced by a composite circuit 14 provided with two integrating circuits 11 and 11' and a composite voltage via a capacitor exceeds a given value, an detecting output is generated. Through detection of reverse polar infrared rays having a time lag, an errorneous output due to outer light, such as solar light, with which the two elements 2 and 3 are simultaneously irradaited, is prevented from occurring, a composite integrating value reduces even at a time when an electric noise is produced to prevent the occurrence of a malfunction, and a reliable detection takes place, which results in obtaining of a high-reliable detector for detecting entrance of a human being.