When Shuji Nakamura, Hiroshi Amano and Isamu Akasaki invented bright blue light from their semi-conductors in the early 1990s, they triggered a fundamental transformation of lighting technology. Red and green diodes existed for a long time but without blue light, white lights could not be created. Despite considerable efforts, both in industry and in the scientific community, the blue LED had remained a challenge for 30 years.
They succeeded where everyone else had failed. Akasaki worked together with Amano at the University of Nagoya, while Nakamura was employed at Nichia Chemicals, a small company in Tokushima. Their inventions lit the world by LED lamps.
White LED lamps emit a bright white light, are long-lasting and energy-efficient. They are constantly improved, getting more efficient with higher luminous flux per unit electrical input power. The most recent record is just over 300 lm/W, which can be compared to 16 for regular light bulbs and close to 70 for fluorescent lamps. As about one fourth of world electricity consumption is used for lighting purposes, the LED’s contribute to saving the Earth’s resources. Materials consumption is also diminished as LED’s last up to 100,000 hours, compared to 1,000 for incandescent bulbs and 10,000 hours for fluorescent lights.
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: due to low power requirements it can be powered by cheap local solar power.
The invention of the efficient blue LED is just twenty years old, but it has already contributed to create white light in an entirely new manner to the benefit of us all.