Three Japanese who succeeded in inventing efficient blue light-emitting diodes (LEDs) where many companies had failed have won the Nobel Prize in Physics.
The Royal Swedish Academy of Sciences on Tuesday announced the award to Isamu Akasaki of Meijo University and Nagoya University, Hiroshi Amano, also of Nagoya University, and Shuji Nakamura of the University of California, Santa Barbara (UCSB).
The three were recognized for their work in the 1990s that enabled the creation of white light using LEDs. While red and green diodes had previously been developed, researchers were unable to develop a blue LED for 30 years. Combining blue with red and green diodes yields white light.
"With the advent of LED lamps we now have more long-lasting and more efficient alternatives to older light sources," the academy said in a release. "Incandescent light bulbs lit the 20th century; the 21st century will be lit by LED lamps."
LED lamps are capable of generating just over 300 lumens per watt (lm/W), compared to 16 lm/W for regular bulbs and nearly 70 lm/W for fluorescent lamps, it added. LEDs can last as long as 100,000 hours. Incandescent light bulbs are typically manufactured with a design life of 1,000 hours, and fluorescents 10,000 hours. Unlike the latter, white LEDs do not contain mercury.
The researchers built their own equipment and engaged in thousands of experiments, focusing on gallium nitride as a material. The work later led to the development of lasers using the blue LED, as well as Blu-ray discs.
"It is very satisfying to see that my dream of LED lighting has become a reality," Nakamura said in a UCSB release. "I hope that energy-efficient LED light bulbs will help reduce energy use and lower the cost of lighting worldwide."
Ten years ago, the Tokyo District Court ordered Nakamura's former employer, LED maker Nichia, to pay him ¥20 billion in compensation (US$180 million) for the invention. He had previously received only ¥20,000 as a bonus. In 2005, Nakamura settled with Nichia, which had appealed, for ¥840 million.
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