Holey foils enter lighting market

05 Jul 2007

Researchers from Illinois are developing flat, flexible plasma lamps that they hope will surpass the efficiency of fluorescent lighting.

A versatile light source based on microcavity plasma technology could be a flexible, efficient and cheaper alternative to conventional lighting, say researchers from the University of Illinois, US. Made from sheets of aluminum foil, the resulting lighting panels are less than 1mm thick and flexible enough to be mounted on a curved surface. (Journal of Physics D 40 3907)

"We expect various applications - for example, we can fabricate disposable UV lamps for treatment of skin diseases or thin flat or flexible lamps (white or any color) for interior designed indoor lamps," Sung-Jin Park, from Illinois' Laboratory for Optical Physics and Engineering, told optics.org. "We are also making devices from silicon, polymer, glass and ceramics, each with their own application."

With current luminous efficacy values of 15 lumens per watt, the researchers hope that further design optimization will yield values exceeding 30 lumens per watt. This would surpass a typical incandescent light which has an efficacy ranging from 10 to 17 lumens per watt.

Each plasma panel consists of two sheets of aluminum foil separated by a thin layer of sapphire. A small cavity penetrates the upper sheet of aluminum foil and the sapphire. A phosphor coated 500 micron thick glass window completes the panel. This brings the overall thickness of the lamp structure to 800 microns - six times thinner than LED panels according to the team.

"As the device can operate in atmospheric pressure or higher, we don't require high vacuum sealing in comparison with conventional incandescent or fluorescent lighting," commented Park. "It can be operated using simple and compact circuits such as batteries or wall plugs."

In initial tests, the team has fabricated thin lamps up to 1 square foot in size. Work is ongoing to optimize the fabrication process, increase luminance efficacy and decrease power consumption.

"We expect the cost would be cut down enormously if it is mass produced," concluded Park. "We are trying hard to commercialize this in the short term but we expect market introduction will take a couple of years."

Park adds that the group has recently established a prototyping company called Eden Park Illumination to develop light sources for several applications.