Light In The Gloom
As well-informed people know, today’s version of low-energy lighting, using compact fluorescent lights (CFLs), is the wrong technology. The products are relatively cheap Class rating of LED lights
to buy, but they have a number of practical disadvantages, as well as significant ecological problems in their production and disposal. Although they are evidently the wrong solution, up to now the right way to go has been too expensive for domestic use.
The brighter future is the light-emitting diode or LED. Based on a far more efficient light source and producing a purer white light, the affordable LED lamp bulb is seemingly within our reach at last. According to Prof Colin Humphreys of Cambridge University’s Centre for Gallium Nitride, the new breed of LED lamp bulbs will last 60 years and could slash the proportion of electricity used for lighting from 20 to just five percent.
In Britain, this could eliminate the need for eight power stations. Even better, the new bulbs do not contain mercury and they are dimmable.
Humphreys says, “We are very close to achieving highly efficient, low-cost white LEDs that can take the place of both traditional and currently available low-energy light bulbs. This could well be the holy grail in terms of providing our lighting needs for the future. That won’t just be good news for the environment; it will also benefit consumers by cutting their electricity bills”.
LED lamps are not new by any means and they are already used widely in torch bulbs, camera flash units, vehicle lights and display lighting in shops, to mention just a few applications. But for ‘general lighting service’ (that’s ordinary lamp bulbs to you and me), the production costs are too expensive for widespread use in homes and offices.
Colin Humphreys’ breakthrough at Cambridge University has been to make the new LEDs from Gallium Nitride (GaN), a man-made semiconductor that emits a brilliant bright light but uses very little electricity. His team has developed a new way of making GaN that could produce LEDs for a tenth of current prices.
The new technique grows GaN on silicon wafers, which achieves a 50 per cent improvement in cost and efficiency on previous approaches employing expensive wafers of sapphire, used since the 1990s. The idea is that commercially-produced versions of Humphreys’ LED will be in use around homes and offices within five years.