LED Lighting has been an important component in an Energy Efficiency program as “ECM” for JLL since Energy Services have been offered. Therefore, an article dedicated to this was worth-value.
Last December 10th 2014, three Japanese-born scientists Isamu Akasaki, Hiroshi Amano and Shuji Nakamura, received the Nobel Physics Prize, due to a discovery that has fostered a revolution in lighting technology: “the invention of efficient blue light emitting diodes that deliver shining light and energy savings,” as the Swedish Academy of Science mentioned in the award.
Akasami and Amano (both based in Nagoya University, in Japan); and Nakamura (California University in Santa Cruz) have been able to create blue light beams with semiconductors by the beginning of 90’s. Both red and green diodes had already existed since final 50s, however, there was a need of finding a third color, the blue one, in order to achieve the summary of the three that produces the white.
LED lighting is more efficient in the sense that it requires less energy to emit light, in comparison with traditional bulbs or fluorescent. Therefore, the most advanced ones can be able to reach a luminous flux of 300 lumen/ Watt, where incandescent bulbs can emit only 16, or fluorescent bulbs can emit 70. In addition, LED do not contain any mercury, therefore they have a socio-economic and environmental importance. Another comparison are the 100,000 hours that LED can last on, against the 1,000 hours from incandescent and the 10,000 hours from fluorescent. It is important to mention that fluorescent light has been called “low consumption,” however, with LED arrival, that “low consumption” appellative has lost its meaning.
A light emitting diode is formed by several layers of semi-conductor materials (light wavelength emitted that depends on the used material) where electricity becomes directly photons, light particles, the efficiency lies exactly in these materials. Traditional luminous sources convert most of the electricity into heat and just a few into light. The electrical current of an incandescent light or halogen warms up a filament that makes incandescent in order to emit light.
Both Akasami and his then doctorate student Amano in Nagoya University, as well as Nakamura working for the Japanese company Nichia Chemicals, chose the gallium nitride as material to get the blue light emitter. The three of them, were entirely dedicated during the 90s to improve the blue light by testing different alloys of gallium nitrite with the use of iridium or aluminum crystals. Besides, the three of them also invented a blue laser with a LED, like the size a sand grain, as essential component.
Due to its very low consumption, LED can work fed by cheap solar panels. This also opens the possibility to improve the quality of life to 1,500 million people in the world who still have no access to electricity grid.