In the ongoing efficiency battle going on between the research labs of the leading high-power white-light LED makers, Cree (Durham, NC) has gained the highest ground, at least for now. The company just announced that it achieved an industry-best reported R&D result of 161 lumens per watt for a white-light power LED.
Cree's tests confirmed that the 1 mm x 1 mm LED produced 173 lumens of light output and achieved its 161 lumens per watt efficacy at a color temperature of 4689 K. The tests were conducted under standard LED test conditions at a drive current of 350 mA, at room temperature. This level of performance is not yet available in production LEDs, says the company.
Such efficiency levels are about ten times that of a standard incandescent bulb, and at least twice that of compact fluorescent bulbs.
The challenge
Every manufacturer of lighting-related high-power white LEDs faces the same challenge: how to bring the cost of LED lighting down to a level where the average consumer will want to take advantage of the high white-light LED efficiencies. Some companies are packaging such LEDs into bulb-sized devices that screw into an ordinary lamp socket and can produce the same amount of light as a 70 to 100 watt incandescent bulb while consuming on the order of 8 to 13 watts of electricity. However, these LED bulbs cost from $70 to $120 per bulb.
At least for now, LED lighting is best-suited for other uses, such as:
--those difficult to achieve with traditional lighting approaches, such as underfloor lighting, changeable colors, and changeable hues (such as warm white/cool white)
--lighting in inaccessible or hard-to-access places, such as outdoor lighting on tall buildings
--illumination for spots that have limited electrical energy available, such as remote outposts or "off-the-grid" solar buildings
However, as LED manufacturers continue to pursue R&D, transfer what they discover into improved products, and expand manufacturing and thus benefit from economies of scale, LED lighting will begin to appeal to the average consumer. At some point, it might even make sense for you or me to buy an LED lamp bulb.
P.S. For the latest news in the areas of not only LEDs but OLEDs (organic LEDs) as well, check out LEDs Magazine.
John Wallace | Senior Technical Editor (1998-2022)
John Wallace was with Laser Focus World for nearly 25 years, retiring in late June 2022. He obtained a bachelor's degree in mechanical engineering and physics at Rutgers University and a master's in optical engineering at the University of Rochester. Before becoming an editor, John worked as an engineer at RCA, Exxon, Eastman Kodak, and GCA Corporation.