Though originally invented back in 1907 by British experimenter H. J. Round, LED's didn't have any real practical application until decades later. Then in the 1960's General Electric began introducing them, available then of course in red. I even remember my first LED digital watch as a kid, and though LED's became popular more recently with budding 'indoor horticulturists' they have yet to penetrate beyond niche markets. Perhaps they are most noticeable, on a daily basis, on your clock radio display, or as the light source of choice in modern traffic lights. But, until now though they have been slow to make any inroads into lighting up our homes.
Despite their longevity and extreme energy efficiency they are just too expensive to manufacture and they have always had one other drawback. The ability to actually project light, Although 70 percent of the energy utilized is converted to light, until recently, only 20 percent of that light created actually escaped the source, the rest was just absorbed by the gallium nitrade semi-conductor diode, which is apparently one of the worst optically friendly materials available.
Dr Faiz Rahman, working at his lab at Glasgow University in Scotland and in conjunction with the Institute of Photonics, University of Strathclyde, Mesophotonics Ltd, and Sharp Laboratories of Europe has developed an amazing system that allows for the millions of microscopic light emitting diodes to project, rather than absorb more of the light energy created.
Though the details are secret, the system relies on developing a precise pattern of microscopic holes on the LED. The holes are small, and when I say small, I mean 200nm, or in layman's terms 400 times thinner than a human hair! The trick is that they are only penetrate 100nm into the surface of the LED and are spaced 300nm apart. 160 holes would create enough to fit across the thickness of a hair, give or take, and a 03mm square chip would provide enough space for literally hundreds of thousands of holes. This configuration essentially creates what Dr Rahman describes as a "photonic crystal" which in a latticed pattern configuration can successfully utilize 80 percent of the light energy created.
The real challenge though was how to create a system that can replicate the pattern efficiently and at a lower cost. Until now nano holes were created by an electron beam which was time consuming and therefore expensive. Rahman and his team have come up with a way of utilizing nanoimprint lithography, that's a form of micro-printing to you and me, enabling a quick and comparatively inexpensive reproduction.
Basically, the LED patterns are duplicated and then imprinted en masse on a stamp sized substrate rather than using a beam to depict each hole. The initial plan is to use the technology in LCD HDTV's for thinner, cheaper screens, but the consensus is that this technology can be used to eventually create cheaper and super efficient light bulbs for the home.
The prediction is that these nanobulbs could be available to consumers within two to three years. It could be the last lightbulb you will ever need to buy. Bright idea huh?