Wednesday, October 8, 2014


The Nobel Prize in Physics 2014- The BLUE LED



The 2014 Nobel Prize for physics is being awarded to three scientists credited with inventing efficient blue LEDs, a development that allowed for the creation of the white LED light sources that are inching toward ubiquity across the globe. Though LEDs of other colors have been around since the mid 1900s, the blue LED proved far more difficult to create as researchers struggled to find a material that would produce blue light. The three researchers being awarded today, Isamu Akasaki, Hiroshi Amano, and Shuji Nakamura, recognized that gallium nitride would lead to a blue color and discovered a way to produce the light in an efficient way by adding in aluminum and indium.


Isamu Akasaki
Photo: Y. Nakamura, Meijo University

Isamu Akasaki

Hiroshi Amano

Hiroshi Amano

Shuji Nakamura

Shuji Nakamura


Red, green, and blue light needs to be combined to create white light, so the work of Akasaki, Amano, and Nakamura provided the final piece to a long-running puzzle. Since then, white LED lights have increased in efficiency and are slowly becoming more prevalent. "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 Royal Swedish Academy of Sciences explains, "due to low power requirements it can be powered by cheap local solar power." The winners will split a prize of 8 million Swedish Krona, or about $1.1 million USD.
"Incandescent light bulbs lit the 20th century," the Academy writes, "the 21st century will be lit by LED lamps."


White Energy-Efficient LED Lamps

The laureates’ inventions made white LED lamps possible. Since LEDs convert electricity directly into light, rather than wasting the majority of energy on heat, “we now have more long-lasting and more efficient alternatives to older light sources,” according to the assembly.
Traditional light bulbs emit light with an efficiency of 16 lumen per watt (lm/W). Fluorescent lights multiply that at 70 lm/W, but current LED lamps leave even those in the dust, with a recent record of roughly 300 lm/W.
“As about one-fourth of world electricity consumption is used for lighting purposes, the highly energy-efficient LED lamps contribute to saving the Earth’s resources,” according to the assembly.

TV, Computer and Phone Screens

Without blue LEDs, televisions, computers, and phones wouldn’t have backlit liquid-crystal display (LCD) screens, which are built with LEDs, according to the assembly. LEDs also provide the flash for camera phones.

Providing Light to Those Without Electricity

LEDs are far more efficient than traditional light sources. In other words, they require less energy to provide light. In the developing world, where more than a billion people live without access to electricity grids, the efficiency of the LED means they can use cheap local solar power instead, according to the assembly.
In many parts of the world, solar-powered LED could replace fuel-powered light, such as kerosene lamps, candles, and open fires, which can be “dangerous, polluting, expensive and dim," Evan Mills, founder of the Lumina Project, told CNN in 2012. “LEDs the size of a cherry can generate light 100 times brighter than a kerosene lamp at a very low wattage, while solar cells have become much more efficient."

Sterilizing Polluted Water

Ultraviolet LEDs, made possible by the blue LEDs, could help sterilize polluted water in the future, according to the assembly, “as UV light destroys the DNA of bacteria, viruses and microorganisms.”

Greenhouse Cultivation

Light on different parts of the spectrum influences plant growth.Because the color of LEDs can be controlled by computers, according to the assembly, that means they can not only provide more efficient lighting in greenhouses, but also more control for growers over their plants.
“Plant scientists all over the world are currently studying this phenomenon in an effort to exploit it in future,” 
“The invention of the blue LED is just 20 years old,” the Nobel Assembly said in its Tuesday press release, “but it has already contributed to create white light in an entirely new manner to the benefit of us all.”

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