Led Lighting

University of Illinois professor Nick Holonyak had no way of knowing in 1962 that someday his own work would rival Thomas Edison’s 125-year old incandescent light bulb. Holonyak was a young researcher at General Electric Company when he built a homemade crystal that glowed red. He still has it in his desk drawer at the university where he is a research scientist. This crude light emitting diode (LED) eventually found its way into alarm clocks, microwave displays, dashboards, automotive headlights and taillights, stoplights, cell phone displays, digital camera flashes, Times Square billboards, accent lighting, refrigerated displays and a growing number of other places.
LEDs are vastly different from traditional incandescent, fluorescent and neon light sources. LEDs stand out because unlike lamps that can shatter, they are robust and highly resistant to shock and vibration. Due to the solid-state nature of LEDs, there are no filaments to break, no moving parts to fail and no glass components of any kind. With LEDs, breakage during transportation, installation or operation – a common problem of traditional light sources – is virtually eliminated. However, LEDs do not currently have the output to replace incandescents or fluorescent technology for general illumination. At least, not yet. By 2015, some analysts say most lights sold for the home will be LED-based. By 2030, it is estimated that 20% of the total lighting market will be LED-based.
The benefits of using LEDs vary depending on the application, but typical technology features include:
Up to 90 percent energy cost savings
A long life of up to 50,000 hours or more
Minimized replacement hassles and costs
Low-voltage operation
Excellent cold-weather performance
Environmental friendliness (LEDs do not contain mercury)
The current lighting market is evolving away from incandescent bulbs. On December 19, 2007, President George W. Bush signed into law a landmark energy bill to begin phasing out traditional incandescent bulbs starting in 2012, to be completed in 2014. The Department of Energy estimates that LED lighting could reduce U.S. energy consumption by 29% by 2025, cutting $125 billion off our national energy bill.
Australia became the first country to ban incandescent bulbs outright starting in 2010.The growing popularity of low-cost and energy-efficient compact fluorescent bulbs will become the standard. But LEDs are beginning to make their move.
Here’s an example of how LED lighting is replacing traditional lighting.
Recently, the Connecticut State House was experiencing short lamp life with HIR+ lamps in conference rooms. In addition, this location has a number of display cases that house historical flags, documents and other precious items. The 40-watt incandescent lamps used in all of the display cases were causing fading and yellowing of these delicate items. In addition, since these cases were lit 24/7, they needed frequent relamping. The customer chose to switch to LED lighting in the display cases due to the cool burning lamp, warm color, easy installation and a 50,000-hour bulb life. The conference rooms will be relamped at a later time when funding becomes available.
The emergence of white LED solutions shows progress toward a new “general illumination” era for LEDs. Over the next several years, continued improvements in white LED color quality and performance are expected to push LEDs into more applications – directly competing with traditional lighting technologies for a share of the “general illumination” market.
Developments are also taking place on a new light source called OLED (organic light-emitting diode). This new type of light is made from wafer-thin materials which can be bent or folded into different shapes for illuminating a workspace or an entire room. GE and Konica Minolta Holdings are in joint development on OLED and have indicated that this material can be punched with holes and woven into fabric. Imagine desktops that light up or perhaps safety hats, vests and gloves.
General Electric Company
University of Illinois Alumni Association
U.S. Department of Energy