Scattered light smoke detector with two two-color LEDs and a common photosensor or with a two-color LED and with two photosensors each in a forward and backward scattering light arrangement

摘要

A scattered-light smoke detector with a detection unit (10) operating according to the scattered-light principle, with first and second light-emitting diodes (1V, 1R) for irradiating particles to be detected and with a common photosensor (2) which is spectrally sensitive, both light-emitting diodes (1V, 1R) in each case a transmission axis (SA) and the photosensor (2) have a reception axis (EA), wherein both light-emitting diodes (1V, 1R) and the photosensor (2) are arranged and aligned with each other such that all three axes (SA, EA) in one common plane (W) lie, wherein the first light emitting diode (1V) with the photosensor (2) at a forward scattering angle (αV) and the second light emitting diode (1R) with the photosensor (2) at a backward scattering angle (αR) is arranged, characterized in that both light-emitting diodes (1V, 1R) each have a first and a second LED chip (3, 4) for emitting a respective first and second light beam (BL, RO) with light in a first and a second light beam of different second wavelength range.