Champaign, IL--A new micro-plasma-based approach to lighting is being commercialized by a company called Eden Park Illumination, which was founded by University of Illinois, Urbana-Champaign researchers Gary Eden and Sung-Jin Park. The research team was funded by the Air Force Office of Scientific Research. By confining plasma in parallel rows of micro-cavities within thin sheet materials, Eden and Park arrived at various implementations of micro-plasma arrays--some that result in inexpensive, wafer-thin, and very flexible sheets of light.
Just as in a fluorescent light, a plasma micro-cavity array (MCA) is energized by an applied voltage. In the Eden Park implementation, a sheet of aluminum foil is placed in an anodizing bath. By controlling the bath parameters, its temperature, and the time of anodizing, large arrays of micro-cavities are formed with near-optimum shape and with automatically placed interconnecting aluminum electrodes. The largest array produced so far contains a quarter million luminous micro-cavities. Thin laminated films on the surface of the wafer contain the electrical power interconnects that feed the individual cavities. When A/C power is supplied through the almost invisible grid, the array emits light.
Many gases can be used to make the micro-plasma arrays; in the process to be commercialized by Eden Park, rare gases produce ultraviolet light and specialty phosphors convert the UV into visible light, as in fluorescent lamps.
The largest arrays currently being produced are six inches square. These can be tiled together, in different colors if desired, to make larger arrays, and if desired, much larger arrays can be made, limited only by the size of the anodizing bath. Aluminum foil is used, with a thickness of 125 microns. The cavities are then sealed in very thin sheets of glass resulting in an array that is one to two millimeters thick. The plasma arrays are ruggedized to a certain extent and have an ultimate thickness of about four millimeters, leaving you with a wafer that weighs less than 200 grams.
While the efficiency of the MCA does not quite measure up to that of LEDs, there is a huge difference in thermal dissipation. MCAs generate far less heat and do not require an aluminum heat sink as LEDs do, allowing MCAs to run much cooler and be more lightweight.
SOURCE: Tech Briefs Media Group; www.greendesignbriefs.com/component/content/article/12377
IMAGE: An illustration shows the component elements of the plasma micro-cavity array for lighting applications. (Courtesy Eden Park Illumination)