The cause was pneumonia, according to an announcement by Meijo University, where Dr. Akasaki had been a professor. He had also been associated with Nagoya University.
Dr. Akasaki was one of three Japanese-born researchers recognized with the 2014 Nobel Prize in physics. His fellow honorees included his onetime graduate student Hiroshi Amano, also of Nagoya University, and Shuji Nakamura of the University of California at Santa Barbara, who conducted much of his work with Nichia Chemicals, a company in Tokushima, Japan.
When the Royal Swedish Academy of Sciences announced the award, the three scientists were described as heirs to the scientific legacy of Thomas Edison, the “Wizard of Menlo Park” who was widely regarded as the father of the incandescent lightbulb.
“Their inventions were revolutionary,” the academy declared at the time, describing the work of Dr. Akasaki and his colleagues. “Incandescent light bulbs lit the 20th century; the 21st century will be lit by LED lamps.”
LED technology, now ubiquitous, is used in televisions, TV remotes, computer screens, smartphones, cars and Christmas tree lights — among myriad applications beyond the LED lightbulbs that are vastly more durable than their incandescent and fluorescent predecessors.
Essentially, an LED is a semiconductor that produces light when an electric current moves through it. Nick Holonyak Jr., an engineer with General Electric, was credited with creating the first practical LED, producing red light, in 1962. Other colors followed, but a blue-light LED proved peskily difficult to build.
Dr. Akasaki, Amano and Nakamura each played a key role in the years-long research that, by the early 1990s, produced semiconductors that used gallium nitride crystals to make blue light.
Blue light, combined with green and red light, produces white light. Because of the extraordinary efficiency of LED bulbs — they can provide up to 100,000 hours of illumination, or 100 times the 1,000 hours offered by incandescent bulbs — their advent was regarded as a breakthrough.
“When Isamu Akasaki, Hiroshi Amano and Shuji Nakamura produced bright blue light beams from their semiconductors in the early 1990s, they triggered a fundamental transformation of lighting technology,” read the Royal Swedish Academy’s news release.
“As about one fourth of world electricity consumption is used for lighting purposes, the LEDs contribute to saving the Earth’s resources,” the announcement continued, also noting that because of its ability to operate on solar power, “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.”
Dr. Akasaki, who was 85 when the Nobel Prize was announced, described himself as a “late bloomer,” according to the Japanese newspaper the Asahi Shimbun. In interviews, he often reflected on the doubts many scientists harbored about blue-light LEDs, regarding them as an impossibility, or at least a development far off in the future.
“Initially, people said this research wouldn’t be completed within the 20th century, so colleagues left, one after another,” the Wall Street Journal quoted Dr. Akasaki as saying when the Nobel Prize was announced. “It never occurred to me to abandon it. I just continued doing what I wanted to do. It didn’t matter to me whether I would succeed or fail.”
Dr. Akasaki was born in Chiran, a town in Kagoshima Prefecture, on Jan. 30, 1929. In a 2014 interview with the Japan Times, his described his delight when his father gave him a collection of minerals. “Why are their colors so very different from each other?” he recalled asking in an early display of his scientific curiosity.
Dr. Akasaki graduated in 1952 from Kyoto University, where he studied electrical engineering. He worked for the electronics company Kobe Kogyo Corp., which later merged with Fujitsu, before receiving a doctorate from Nagoya University in 1964.
Dr. Akasaki then joined the Matsushita Research Institute in Tokyo, where he worked until moving to Nagoya University in 1981 and then Meijo University in 1992. A complete list of survivors was not immediately available.
In addition to the Nobel Prize, Dr. Akasaki’s honors included a 2009 Kyoto Prize — Japan’s highest honor — recognizing developments in advanced technology. He found that some technology, however, needed no advancing at all. He took great pleasure, for example, in long-playing classical music records.
On that point, he joked, “I am analog.”
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