The spirit of Alfred Nobel has prevailed this year as the committee of the Swedish Royal Academy awards the Nobel Prize for Physics to three scientists whose investigations will be of great benefit to mankind: they have invented “efficient blue light-emitting diodes which have enabled bright and energy-saving white light sources,” in other words, long-lasting LED bulbs. The award winners are the three Japanese scientists, Isamu Akasaki, Hiroshi Amano and Shuji Nakamura, the latter now a citizen of the United States.
Given that LED lights form part of most people’s everyday lives, perhaps we don’t notice their true value, but they represent a significant advance in global energy savings. A quarter of all energy consumption is due to lighting. The image below shows how energy efficiency in terms of lighting systems has evolved over time.
What Is the Contribution of the Efficient Blue LED?
Henry Joseph Round was the first scientist to discover the basic principle of LEDs: certain semiconductors emit light when an electric current passes through them. Later, in 1927, Oleg Vladimirovich Lósev published the first study on the subject, but the first LED in the visible spectrum was not invented until 1962, with an emission of red light. This development came from the American engineer Nick Holonyak, who predicted 50 years ago that LED bulbs would replace conventional incandescent bulbs. So, why does the invention of the blue LED merit the Nobel Prize for Physics? The simple answer, without delving into complex scientific explanations about semiconductor quantum theory, is that the blue diode has unique properties, which permit the creation of white light in the current efficient bulbs (the sum of red, green and blue). Creating the blue diode without losing the properties of the semiconductors they use was complicated and costly. The three award-winning scientists worked against the established scientific currents and failed in hundreds of experiments before achieving their goal. Indeed, the scientific community and industry had also spent decades fruitlessly endeavouring to overcome the challenge.
In the early stages, LEDs were not highly efficient, but over the years this has changed: they require much less energy to emit light or, to put it another way, they use up to 80% of the energy they consume and convert it into light (compared with only 20% in conventional bulbs). Now we can find LED bulbs with 300 lumens per watt (fluorescent bulbs have around 70), with a duration of approximately 100,000 hours (fluorescent bulbs last for only 10,000 hours).
LED bulbs are also improving the quality of life for millions of people who have no access to the electricity network: owing to their very low consumption, a low-cost solar panel is all that is needed to provide the energy to light them. Moreover, as they do not contain mercury, they are less harmful to the environment
If one travels mentally through one’s daily life, it is easy to realise how omnipresent these LED bulbs are. They are used in camera flashes, in our mobile phones, tablets, computers and cars, in digital watches and clocks, in street lighting in many cities, in traffic signals, in building and shop signs, in all types of electronic panels (including our generator set consoles), and so on. At Inmesol we also use LED technology in the spotlights for all our lighting tower models to make them more efficient