Unlike incandescent and fluorescent lamps, solid-state lighting creates light without producing heat. A semi-conducting material converts electricity directly into light, which makes the light very energy efficient. Solid-state lighting includes a variety of light producing semiconductor devices including light-emitting diodes (LEDs) and organic light-emitting diodes (OLEDs).
Until recently, LEDs-basically tiny light bulbs that fit easily into an electrical circuit-were used as simple indicator lamps in electronics and toys. But they can be as bright as incandescent lamps. And the cost of semiconductor material, which used to be quite expensive, has plummeted, making LEDs a more cost-effective lighting option.
Research shows that LEDs have great potential energy efficient lighting for residential and even commercial building use. New uses for LEDs include small area lighting, such as task and under-shelf fixtures, decorative lighting, and pathway and step marking. As white LEDs become more powerful and effective, LEDs will be used in more general illumination applications, perhaps with entire walls and ceilings becoming the lighting system. They're already being used successfully in many general illumination applications including traffic signals and exit signs.
OLEDs currently are used in very thin, flat display screens, such as those in portable televisions, some vehicle dashboard readouts, and in postage-stamp-sized data screens built into pilots helmet visors. Because OLEDs emit their own light and can be incorporated into arrays on very thin, flexible materials, they also could be used to fashion large, extremely thin panels for light sources in buildings.