Smoke alarm according to the scattered light principle having a two-color light-emitting diode with different sizes of LED chips

  • US 9,569,946 B2
  • Filed: 02/13/2015
  • Issued: 02/14/2017
  • Est. Priority Date: 02/13/2014
  • Status: Active Grant
First Claim
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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.

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