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Nobel Prize for Physics 2014: why blue LEDs have changed the world

This year's Nobel Prize for Physics has gone to three Japanese scientists who gave us blue light-emitting diodes, used daily in traffic lights

By Philip Ball  

The victory of the three Nobel Prize-winning scientists is celebrated in Tokyo during a lunar eclipse ©The Yomiuri Shimbun via AP Images

Did you notice when traffic lights began to change colour? The green “go” light was once a yellowish pea green, but today it has a turquoise hue. And whereas the lights would switch with a brief moment of fading up and down, now they…

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