Solid state lighting (SSL) is the general descriptor for forms of illumination in which light is “emitted from a solid object - a block of semiconductor - rather than from a vacuum or gas tube, as in the case of incandescent and fluorescent lighting,” (as defined by Sandia National Laboratories, a DOE-sponsored research lab). SSL presently comes in two flavors: inorganic LEDs and organic light-emitting diodes (OLEDs). We’ve all seen LEDs, which are typically smaller than a pea. OLEDs, however, may be ‘painted’ onto flat areas, creating luminous surfaces. While OLED applications are still in the development stage, LEDs are all around us in instrument lights, exit signs, traffic lights, decorative and novelty lighting, automotive tail lights, and a variety of other uses.
The technology is developing rapidly, and it is supported by both industry and government. Find a good FAQ at www.sandia.gov/lighting/XlightingoverviewFAQ.htm.