Smoke detection unit with light-emitting diode and photo-detector, and with an LED chip arranged in the light-emitting diode and with a photosensor for determining a degree of aging and/or a compensation value for a light current, as well as a light-emitting diode

摘要

An optical smoke detection unit for a danger alarm includes a light-emitting diode (LED) including at least one LED chip in an LED housing and connection contacts contacting the LED chip and running out of the LED housing. The smoke detection unit may include a photo-detector spectrally sensitive to emitted light for detecting smoke and a control unit for controlling the LED and for evaluating a sensor signal of the photo-detector for characteristic fire magnitudes. The LED may include a photosensor spectrally sensitive to the emitted light. The control unit may detect an electrical characteristic magnitude of the photosensor while providing electrical control of the LED, and based on the detected electrical characteristic magnitude, (a) derive and output ageing information about the LED and/or (b) determine a reduction of light current of the LED and modify the electrical control of LED to correct such reduction.