- on Education & Information
- Published in issue 4/2003 on page 0
matrixed clusters for lighting purposes
A handful of high-intensity LEDs is sure to provide new accents in room lighting. In traffic lights and other signalling equipment, they save energy and reduce maintenance cost thanks to their long life expectancy as compared with conventional lamps.Manufacturers have been able to push the light intensity of modern LEDs to levels where these devices can be used for lighting (illumination) purposes, even if prices are still relatively high. However, LEDs do offer some clear advantages over traditional electrical light sources. For one thing, their life expectancy of up to 100,000 hours is impressive. Also, the optics are integrated in the enclosure to ensure the emitted light is bundled to requirements. A further advantage is the fast on/off time of a LED. In cars, for example, a LED brake light gives a clearly faster response than a conventional bulb. Whereas LEDs respond within 100 ns or so, ‘cold’ bulbs need to be pre-heated for about 100-300 ms. During that period, they require current peaks of up to 50 times their nominal value.