I first learned about the future and promise of LEDs at a Las Vegas trade show maybe six or seven years ago. I asked how long it might be before they were ready for the marketplace, and they told me, "three to five years."
Last year, when AIA came to Boston, I stopped by the Philips Color Kinetics booth and asked the same question, among others, and the answer was, "three to five years."
That's probably just a coincidence, but it does seem that LEDs have stayed out there on the horizon, at least for household use. But now there may have been a breakthrough, reported by Alok Jha of the Guardian newspaper in Britain:
Colin Humphreys of Cambridge University led a team that has successfully made white LEDs from gallium nitride. This semiconductor has been around for decades but it has been expensive to produce (grown on wafers of sapphire) and the light it can produce is usually blue or green.
Humphreys has found a way to grow the gallium nitride on silicon wafers, making it 10 times cheaper. And by applying a phosphor to the LED, they can shine more useful white light. Within five years, Humphreys hopes to have commercially-produced versions of his LED in use around homes and offices.
Yes, I do note the "within five years" phrase, but I find credibility in the specificity of what has changed.
The report says Humphreys has calculated that in Britain, widespread adoption of the new technology would lower the percentage of electricity devoted to lighting from 20 percent to 5 percent, enough to remove the need for eight coal-fired power plants