Monday, October 13, 2014

SCIENCE SPECIAL..................... American and 2 Japanese Physicists Share Nobel for Work on LED Lights

American and 2 Japanese Physicists Share Nobel for Work on LED Lights


The 2014 physics award went to Isamu Akasaki and Hiroshi Amano of Japan and Shuji Nakamura of the University of California, Santa Barbara, for “the invention of efficient blue light-emitting diodes, which has enabled bright and energy-saving white light sources.”
The three scientists, working together and separately, found a way to produce blue light beams from semiconductors in the early 1990s. Others had produced red and green diodes, but without blue diodes, white light could not be produced, the Royal Swedish Academy of Sciences said on Tuesday morning in its prize citation.
They succeeded where everyone else had failed,” the academy said.
Their work has spurred the creation of a whole new industry. The committee that chose the winners said light-emitting diodes, or LEDs, would be the lighting source of the 21st century, just as the incandescent bulb illuminated the 20th.
Dr. Akasaki, 85, of Meijo University and Nagoya University, and Dr. Amano, 54, of Nagoya University, are Japanese. Dr. Nakamura, 60, is American. Awakened by a phone call from the Swedish academy, he described it in a news conference as “unbelievable.”
In its announcement, the academy recalled Alfred Nobel’s desire that his prize be awarded for something that benefited humankind, noting that one-fourth of the world’s electrical energy consumption goes to producing light. This, it said, was a prize more for invention than for discovery.
Frances Saunders, president of the Institute of Physics, a worldwide scientific organization based in London, agreed with those sentiments. Noting in an email statement that 2015 is the International Year of Light, she said, “This is physics research that is having a direct impact on the grandest of scales, helping protect our environment, as well as turning up in our everyday electronic gadgets.”
In Africa, millions of diode lamps that run on solar power have been handed out to replace polluting kerosene lamps.
For the same amount of energy consumption, LED bulbs produce four times the light of a fluorescent bulb and nearly 20 times the light of an incandescent bulb
LED bulbs are also more durable, lasting 10 times as long as a fluorescent bulb and 100 times as long as an incandescent bulb.
Light-emitting diodes are already ubiquitous — in pockets and purses, in smartphones, as well as in televisions, lasers and optical storage devices.
And their future is vaster still. “The LED lamp holds great promise for increasing the quality of life for over 1.5 billion people around the world who lack access to electricity grids,” the Nobel committee said. “Due to low power requirements, it can be powered by cheap local solar power.”
The work rewarded on Tuesday was the latest step in an evolution that began with Thomas Edison’s burning out light-bulb candidates in his Menlo Park laboratory in the late 19th century.
Incandescent bulbs use electricity to produce heat in a glowing filament that emits a comparatively small amount of light; fluorescent lights use a gas.
Light-emitting diodes are based on the same quantum magic that gave birth to computers, smartphones, transistor radios and all other electronic devices.
The diodes are no bigger than a grain of sand and consist of sandwiches of semiconducting materials. When an electric field is applied, negative and positive charges meet in the middle layer and combine to produce photons of light. The color of the light produced depends on the type of semiconductor.
Nick Holonyak Jr. of the University of Illinois, who invented the first red-light diode in 1962, has called the LED the “ultimate lamp” because “the current itself is the light.”
Red- and green-emitting diodes have been around for a long time, but nobody knew how to make a blue one, which was needed for blending with the others to create white light. The amount of information that can be packed into a light wave increases as its wavelength shortens, making blue the color of choice for conveying information.
That is where the new laureates, working independently, came in. The key was to grow high-quality crystals of gallium nitride, a semiconductor for producing blue light — a process that had frustrated researchers.
Dr. Akasaki first tried to grow the crystals in the late 1960s as a young research associate at Matsushita Research Institute in Tokyo. It was not until 1986 that he and Dr. Amano, who was then his graduate student, succeeded in growing high-quality crystals on a layer of sapphire coated with aluminum nitride, and found out their properties were enhanced when they were scanned with an electron beam.
The royalties from their work subsequently funded the construction of a whole new research institute, the Nagoya University Akasaki Institute.
Dr. Nakamura, then at the Nichia Corporation, a chemical engineering and manufacturing company, succeeded in growing his own crystals, improving on the other two scientists’ method. In 2006 he was awarded the Millennium Technology Prize of one million euros (about $1.3 million) for inventing the first efficient blue-light laser, opening the way for things like Blu-ray players.
Dr. Nakamura left Nichia in 1999 to join the University of California, Santa Barbara. Two years later, in a shocking challenge to Japanese traditions of subservience, he sued the company for 20 billion yen, $193 million at the time, saying he deserved a share of royalties for his inventions. Nichia had given him an award of 20,000 yen — about $200 — for his contributions to the company.
A court awarded him the full amount, but the company appealed. In 2005 he and the company settled for a payment of 843 million yen, or about $8.1 million.
As is often the case with Nobel Prizes, not everybody was happy on Tuesday. The prize can be awarded to no more than three people, and Dr. Holonyak expressed dismay that various American scientists who had laid the framework were left out.
We’re always tugging and pulling,” he said in a telephone interview from Illinois. “Nobody is smart enough to know all this.”


By DENNIS OVERBYEOCT. 7, 2014


No comments: