Luminescent emitters
A luminescence emitter is a light source that generates light from a luminescence process and not from a glowing body ( thermal radiation ), as is the case with incandescent lamps .
The luminescent lamps include gas discharge lamps such. B. the fluorescent tube or the sodium vapor lamp . Here atoms ( mercury in fluorescent tubes, sodium in sodium vapor lamps) are stimulated by shocks and the energy is released again through a fluorescence process .
Another class of luminescent emitters uses electroluminescence . These include inorganic light-emitting diodes (LEDs) and organic light-emitting diodes (OLEDs) as well as electroluminescent films . The light is generated in a solid by applying an electrical voltage or an electrical field .
Luminescence emitters show completely different spectra depending on the design, starting with the line spectrum through band spectra to continuous spectra. In the fluorescent tube, for example, is the invisible UV -Light by a fluorescent in a band spectrum converted that appears white to the human eye. The sodium vapor lamp shows a line spectrum with an orange line. The efficiency of this lamp is extremely high, but the color rendering is poor so that sodium lamps are only suitable for special purposes, e.g. street lighting.
Efficiency
The efficiency is typically 40 to 99 percent.
literature
- Hans R. Ris: Lighting technology for practitioners. 2nd Edition. VDE-Verlag, Berlin / Offenbach 1997, ISBN 3-8007-2163-5 .
- Bo Hanus: Practical solar applications with light emitting diodes. Franzis Verlag, Poing 2007, ISBN 978-3-7723-4410-7 .