With the aim of developing a low-energy light bulb which works without mercury, Russian scientists and scientists from Chalmers University of Technology in Sweden have worked together to develop a field emission cathode, a cold cathode which produces a flow of electrons. The benefit over traditional hot cathodes is the reduction in heat loss. Hot cathodes can be found in devices such as old television sets, where the electrons radiate out from a heating filament which generates heat and consumes energy.
The company, LightLab Sweden AB has developed an environmentally-adapted energy-saving light bulb. It is based around a unique method of producing light completely without mercury and other environmentally-harmful substances. The technology is called field emission, and can be used both in general domestic light fittings and in new, exciting applications.
Present-day fluorescent tubes and energy-saving light bulbs depend on mercury to function, so they contribute to the release of environmentally-hazardous substances into the environment. In low temperature environments, energy-saving light bulbs perform poorly or not at all. Nor can they be used with a dimmer switch. LightLab’s light bulbs work in all temperatures and the light can be dimmed. All users have probably also noticed that today’s energy-saving light bulbs emit a cold light, i.e. a somewhat blue light which makes people’s faces look grey. The light bulbs produced by LightLab can be made with any colour spectrum.
Work still has to be carried out before the light bulbs become available in the shops. The technology involved is highly advanced, and scientists are currently fine-tuning all the components: the porous carbon cathode, the luminescent material on the inside of the glass and the control electronics.
This article was first published in Advantage Environment printed in February 2008