Cree has made a one-off light bulb technology demonstrator, pulling out all the stops to exceed performance goals set by the US Department of Energy (DOE) for its '21st century lamp' concept, writes Steve Bush.

Made by the firm's research and development team, the lamp delivers more than 1,300 lumens at 152 lm/W with good colour rendering and warm white emission.

"Not long ago, fixture efficacy of 100+ lm/W was impossible, but Cree is shipping fixtures at 110 lm/W today," said Cree co-founder Neal Hunter, "We calculate that if fully deployed, LED lighting at 150 lm/W could bring a 16.5%  reduction in the US's electric energy consumption, returning it to 1987 levels."

Independent lab OnSpeX measured 1,330 lm at 8.7W at a credible 91 colour rendering index and colour temperature of 2,800K.

"LED lighting at this level of performance is only made possible by advancements across all elements - lighting-class LEDs, optical elements, drivers and power supplies. Optimising each element was critical," said Cree.

The US Energy Independence and Security Act of 2007 directed the DOE to establish the 'Bright Tomorrow L Prize' competition. The 21st Century Lamp competition is a third, still not fully-defined category in the legislation, joining competitions to create replacements for 60W incandescent lamps and PAR 38 halogen lamps.
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The preliminary specifications for the 21st Century Lamp include:
>1200 lm
>150 lm/W
>90 CRI
2,800-3,000K colour temperature

Cree's lamp development was part funded by the DOE.