Scattered-light smoke detector with a two-color light-emitting diode

摘要

A scattered-light smoke detector includes a detector unit that operates according to the scattered-light principle. The detector unit includes a light-emitting diode (LED) to irradiate particles to be detected and a spectrally sensitive photosensor to detect the light scattered by the particles. The LED and photosensor are aligned such that a principal optical axis of the LED and a principal optical axis of the photosensor define a scattered-light angle. The LED includes a first and a second LED chip for emitting first and second light beams with light in a first wavelength range and a different second wavelength range, and an LED chip carrier arranged orthogonally to the principal optical axis. The two LED chips are arranged side-by-side on the LED chip carrier. The LED is rotated such that a chip axis extending through the two LED chips is orthogonal to an angle plane defined by the two optical axes.

主权项

1. A scattered-light smoke detector with a detector unit that works according to the scattered-light principle, the scattered-light smoke detector comprising:
a light-emitting diode configured to irradiate particles to be detected, and a photosensor that is spectrally sensitive to the particles to detect light scattered by the particles, wherein the light-emitting diode has a principal optical axis and the photosensor has an optical receiving axis, wherein the light-emitting diode and the photosensor are arranged and aligned with respect to each other such that the principal optical axis of the light-emitting diode and the optical receiving axis of the photosensor define a scattered-light angle, wherein the light-emitting diode comprises a first LED chip configured to emit a first light beam with light in a first wavelength range and a second LED chip configured to emit a second light beam with light in a second wavelength range different from the first wavelength range, wherein the light-emitting diode comprises an LED chip carrier arranged orthogonally to the principal optical axis of the light-emitting diode , wherein the two LED chips are arranged side-by-side on the LED chip carrier, and wherein the light-emitting diode is rotated about the principal optical axis such that a chip axis extending through the first and second LED chips is orthogonal to an angle plane defined by the principal optical axis of the light-emitting diode and the optical receiving axis of the photosensor.