The Electroluminescent Display

Electroluminescence is a physical process involving, as its name makes clear, an electrical current and visible light. To be more precise, is it a phenomenon in which an electrical current passing through a material, or the presence of an electric field in close proximity to a material, will cause that material to emit light. During electroluminescence, the electrical current flowing through the substance excites the electrons in the atoms that it passes through, causing them to release energy in the form of a photon. When added together, the combined photon release from a very large number of atoms across the length and width of the conductive surface form a soft but potentially very clear and highly visible glow.

An electroluminescent display, or ELD, is the technological harnessing of this phenomenon. The display is put together by sandwiching several layers together - a lower layer of electrode strips, a thin sheet of electroluminescent material on top of it, a second layer of electrode strips running at 90 degree angles to the lower layer, and a thin transparent sheet at the very top to keep it all in place and allow the light created to escape. The two layers of electrode strips, perpendicular to one another, form a type of grid when they are set in place. At each intersection of the grid, where a point on the lower electrode layer meets a point on the upper electrode layer, the material is excited to the point of releasing light. The color of light produced is dependent upon the exact nature of the material being employed in the ELD.

There are several significant advantages to ELD's in the particular uses that they are commonly put to - soft area lighting, instrument panel lighting, and to serve as the backlight for liquid-crystal displays and other similar visual information displays. ELD's use very little power when compared with most other common forms of artificial lighting. They can serve in places where a light is desired to be on for very long periods of time while minimizing consumption. Second, they do not generate heat, unlike incandescent lights. ELD's can be made to glow in a variety of colors and form clear images, and their use in illuminated signs has created a cheaper alternative to more traditional, power-hungry forms of illumination. The low power consumption and lack of heat make ELD's excellent for very many display purposes.