One man's discovery

Shuji Nakamura invented blue LEDs back in the 1990s.

Now, after years of mass production, the price of these LEDs is now beginning to affect society. How?

* The most obvious is that Blue LEDs are used in the next generation of DVD player. His invention has obviously meant that DVDs can carry more information. Great for us film buffs.

* The technology he invented has also meant the development of pure white LEDs, which are also now quite cheap. White LEDs use much less energy to produce light. White LEDs are therefore going to be important as a substitute light source if society cuts down its energy use to reduce greenhouse gases.

* The technology he invented has also meant the development of ultra-violet LEDs, which are now being used to sterilize drinking water - a boon for third world nations needing cost-effective water treatment.