Patent ID: 9569946
Date: 2017-02-14
CPC Classifications: G08B,H01L

Claim:
1. An optical smoke alarm, comprising: a detector unit working according to a scattered light principle; a light-emitting diode for irradiating particles to be detected and disposed in said detector unit, said light-emitting diode having a first LED chip being a surface-emitting radiator for emitting a first light bundle with light in a first wavelength range of 350 nm to 500 nm, said light-emitting diode having a second LED chip being a surface-emitting radiator for emitting a second light bundle with light in a second wavelength range of 665 nm to 1000 nm, said first and second LED chips are disposed next to each other, a ratio of an optically active surface of said first LED chip to an optically active surface of said second LED chip being within a range of 2 to 20; and a spectrally sensitive photosensor to detect light scattered by the particles, said spectrally sensitive photosensor disposed in said detector unit.