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First Energy-Efficient, LED-Based Task Lamp Brought to Market

The first task lamp using energy-efficient light-emitting diodes (LEDs) to provide illumination has hit the marketplace. Research conducted by Stephen Johnson, a scientist at the Environmental Energy Technologies Division of Lawrence Berkeley National Laboratory, helped lamp manufacturer Luxo USA Corporation develop the LED lighting systems that led to the new product.

Image of LED-Based Task Lamp

Figure 1. Luxo's LED Arketto, the first task lamp to use energy-efficient light-emitting diodes as its light source.

Luxo's "LED Arketto" uses three 3-watt LEDs but provides more usable light than the comparable 40-watt halogen that it will replace due to the higher efficiency of the source and better optical control of the light. Luxo introduced the lamp at LightFair, the largest U.S. architectural and commercial lighting trade show, in New York City earlier this year.

LEDs are the key to the next generation of energy-efficient lighting in buildings. Small light-emitting chips, once found mainly in old-style electronic displays, are now common in a variety of signal devices-for example, traffic lights, electronic signboards, hazard lights, and in automobiles in blinkers, dashboards, and brake lamps.

Lighting researchers believe that as LEDs improve, their application in both residential and commercial spaces could cut worldwide lighting electricity use in half. The magnitude of this reduction would decrease the world's total electricity use by up to 10 percent, and its emissions of greenhouse gases by about 10 percent as well. Researchers at Berkeley Lab and elsewhere are working to improve the technology to the point where it is a viable commercial alternative to existing technologies for general lighting.

Luxo's Arketto LED resulted from extensive R&D by the manufacturer, with the help of technical advice and support from Johnson. Johnson is head of EETD's Lighting Group. Luxo's corporate headquarters are in Oslo, Norway.

Luxo Corporation was the company that introduced the first adjustable-arm task lamp in the 1930s. The spring-loaded design allowed the user to move the head of the lamp to any position over the table. The company's new LED task light uses LEDs and an advanced reflector design to diffuse the light over a work area about three feet-by-four feet when the head of the lamp is 18 inches from the work plane. At this level, the Luxo LED lamp puts more light on a desk than a 40-watt halogen lamp. The head is mounted on a flexible arm that can be adjusted over the work surface. The Arketto design has won awards for Luxo in a number of interior design competitions.

"This is the most R&D-intensive product that we've developed in the last 20 years," said Luxo's Product Manager Dave Shepard. "We spent the last year figuring out how to turn LEDs into a product for real-world applications."

Johnson's association with Luxo actually began with a research project funded by the California Energy Commission's Public Interest Energy Research Program. The work's purpose was to develop an LED-based task light suitable for the general illumination market. Johnson worked with Berkeley Lab researchers, plus industrial partners Luxo, Cree Lighting (which manufactures LEDs), Advance Transformer, and Permlight. The team built a prototype lamp using commercially available materials, including one-watt LEDs mounted on copper-clad fiberglass-core boards, connected to aluminum heat sinks.

Their prototype generated distribution of light similar to a commercial lamp using a compact fluorescent light source, but it was only half as energy-efficient. They needed better optics to distribute the LED's light, improved color quality, and a better system for removing heat from the LED. If the LED is too hot, its life and light output both decrease.

The project team worked together to solve the problems of the initial prototype, and they ended up with a new prototype that operated at 11 watts of LED power but had the light distribution and intensity of a Luxo task lamp using an 18-watt compact fluorescent lamp (CFL). "The results of this program stimulated Luxo to generate an aesthetically improved version of this concept using their new Arketto task lamp design," says Johnson.

Luxo looked at the results of Johnson's research and developed several prototype designs of its own. The first lamp prototype using the three 3W-LEDs did not put as much light on the surface of the work plane as they wanted, so they developed improved optics.

"We had to figure out how to pick up all of the light from the LED chip," says Shepard. "We did three months of optical modeling to figure out how to do this…We can really bend and shape the light and put it where we want it," says Shepard. He adds that Johnson played an important role in the process. "Steve pushed us into believing that we could use LEDs in a commercial product. The lighting industry believed that LEDs were not yet ready for primetime."

Luxo is hoping to interest the designers of commercial office furniture into using their energy-efficient Arketto lamp for built-in fixtures. "More and more companies are interested in buildings that meet (industry) standards and other energy-efficiency codes," says Shepard.

Members of the Berkeley Lab research team included Akos Borbely, Neil Fromer, Tal Margalith, and Jim Galvin. Sam Gumins of Luxo USA; Erlend Lillelien, Luxo, Norway; Manuel Lynch, Permlight; James Ibbetson, Cree Lighting; and Julio Vera, Advance Transformer, were the industrial partners.

— Stephen Johnson

For more information, contact:

  • Stephen Johnson
  • (510) 486-4274; Fax (510) 486-4089

Lighting Resource Group

Luxo USA Corporation

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