Scientists working for Ceravision, a company based in Milton Keynes, in Britain, have designed a new form of lamp that eliminates the need for electrodes, reported The Economist (8/9/2007, p.4). Their device uses microwaves to transform electricity into light. It consists of a relatively small lump of aluminium oxide into which a hole has been bored, with a gas-capsule, inside. The lot is bombarded with microwaves generated from the same sort of device that powers a microwave oven. As electrons accelerate in the electric field, they gain energy that they pass on to the atoms and molecules of the gas as they collide with them, creating a glowing plasma. The resulting light is bright, and the process is energy-efficient.
Energy efficiency greater than 50 per cent: Indeed, whereas traditional light bulbs emit just 5 per cent of their energy as light, and fluorescent tubes about 15 per cent, the Ceravision lamp has an energy efficiency greater than 50 per cent. The lamp’s small size makes them compatible to light-emitting diodes but the new lamp generates much brighter light than those semiconductor devices do.
Cheap, and does not need mercury: A single microwave generator can be used to power several lamps. Another environmental advantage of the new design is that it does not need mercury, a highly toxic metal found in most of the bulbs used today, including energy-saving fluorescent bulbs, fluorescent tubes and high-pressure bulbs used in projectors. And Ceravision also reckons it should be cheap to make. With lighting accounting for some 20 per cent of electricity use worldwide, switching to a more efficient system could both save energy and reduce emissions of climate-changing greenhouse gases.
The Economist, 8/9/2007, p. 4