Edison's Legacy

How is it that lighting, something so seemingly within reach of current scientific capability, is actually proving so complicated to evolve? Colour, functionality, brightness, cost, environmental soundness, disposability... all are equally important factors, and it is tricky to achieve all of them at once. today’s technological advances have bred many permutations on the beloved incandescent light bulb, though none of these is as yet a viable contender, at least not in regard to human perception.