<p>The unused and initially non-visible UV-radiation of mercury discharge lamps is converted into visible light by flourescent phosphons. For example in fluorescent and compact fluorescent lamps. In Light Emitting Diodes (LEDs) light will be emitted in a relatively small waveband of the spectrum by the reversal of the principle of the diode with the application of a forward voltage (forward biased). The emitted wavelength of light is determined by the technology used (substrate configuration) or doping of semiconductor materials.</p> <div></div> <p><img class="buttons square13 zippy-plus" src="http://www.google.com/images/cleardot.gif" border="0" /></p>