Ballon Generali diameter of . It has been used as advertising billboard for Fortis, then from 2002 for Eutelsat. In 2008, a partnership has been signed with Banque populaire and Airparif : renamed "ballon Air de Paris", its internal illumination system changes the outer colour in real-time, according to the ambient air pollution in Paris, measured by Airparif : from green (good) to red (bad) through orange (poor). This system was completed by an independent lighting (panels light-emitting diode, visible especially at night on the lower part of the shell) stating the air quality near traffic with the same colour code. On
Light-emitting diode epoxy, synthetic rubber or silicone. Touching bare LEDs using synthetic rubber or silicone can damage the delicate wire bonds from LED to package or the LED itself, so they may be protected by a plastic or glass cover, such as in the LED flash in smartphones. It is this YAG phosphor which causes white LEDs without diffusers (such as those used in LED lamps and bulbs) to look yellow when off. There are three main methods of mixing colors to produce white light from an LED: Because of metamerism, it is possible to have quite different spectra that appear white.