LEDs for lighting?
White LED versions of traditional luminaires are already available from several manufacturers, particularly in the MR11 spotlight style. LED headlights for cars are in the pipeline, notably through the work of Germany’s Osram, which is producing a range of multi-die packages that are close to producing enough light for road illumination. LED bicycle headlights are already available. Reality checking Firstly, firms which claim 90 per cent efficiency from LED light sources are making it up. Even the latest ones convert far more electricity to heat than they do to light. Next, according lighting industry experts, LEDs will remain expensive compared with light bulbs and florescent tubes. And whilst they will increasingly appear in homes and offices, they will almost certainly will not replace florescent tubes in office lighting. Florescent tubes, at 100 lm/W for the best fittings, are equal in electrical efficiency to the best LEDs. In the future, large area sheet emitters based on organic
