On October 7, the Royal Swedish Academy of Sciences in Stockholm named the winners of 2014 Nobel Prize in physics. Isamu Akasaki and Hiroshi Amano of Nagoya University in Japan and Shuji Nakamura, who now works at the University of California, Santa Barbara, will split the roughly $1.1 million award. Nakamura made his early contributions to LEDs while at Nichia Chemicals in Tokushima, Japan.
Their achievement was creating a building block of white LEDs 20 years ago: the blue LED.
To create white light using LEDs, a device must combine at least three different wavelengths (colors). Engineers typically mix the three primary colors: red, green and blue.
Although red and green LEDs have existed for about 50 years, back in the late 1980s, a blue LED was still only a dream. Many companies set teams of their researchers to work creating one. They all failed, Delsing, physicist at Chalmers University of Technology in Göteborg, Sweden, says. But in Japan, three scientists kept trying. Eventually, he notes, their efforts paid off.
LEDs convert up to 50 percent of electrical energy entering them into light. The most recent record is an LED that converts one watt of power into slightly more than 300 lumens of light. That’s much better than the 70 lumens per watt achieved by fluorescent lights. And it far surpasses the paltry 15 lumens per watt offered by those old-school incandescent light bulbs. That’s one reason the sale of incandescent lights is being phased out in many parts of the world. Another reason: Other types of lights, especially LEDs, last much, much longer.
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