L Prize

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The L Prize (aka the Bright Tomorrow Lighting Prize) is a competition run by the United States Department of Energy aimed to "spur lighting manufacturers to develop high-quality, high-efficiency solid-state lighting products to replace the common incandescent light bulb".[1]

The competition, launched in May 2008 at Lightfair, offers two prizes for the replacement of two types of bulb, an A19 60-watt incandescent light bulb and a PAR 38 halogen incandescent bulb. The prize fund for the 60 W replacement is up to a maximum of US$10 million and for the PAR 38 up to US$5 million.[2] There is a third category, yet to be publicly defined, called the 21st century lamp.[3]

The competition has set out various qualifying requirements for the replacement bulbs summarized in the table below:

60 W Incandescent Replacement bulb PAR 38 Halogen Replacement bulb 21st Century Lamp (Preliminary)[4]
More than 90 lm/W More than 123 lm/W More than 150 lm/W
Less than 10 watts Less than 11 watts
More than 900 lumens More than 1,350 lumens More than 1200 lumens
More than 25,000-hour life More than 25,000-hour life
More than 90 CRI More than 90 CRI More than 90 CRI
2700–3000 K CCT 2700–3000 K CCT 2800-3000 K CCT

Winner[edit]

It was announced on 3 August 2011, that the winner of the 60 W replacement bulb competition was a bulb made by Philips.[5][6] The winning bulb was a LED lamp using less than 10 watts and emitting the equivalent amount of light as a traditional 60 watt incandescent bulb. That amounts to an 83% energy savings. It was announced that Philips would be given the US$10 million cash prize.[5][6] The bulb was released commercially in February 2012 through several online sellers. The widespread launch at retail stores, however, was not until Earth Day, April 22.[7] Although the subsidized price was expected to be $22 in the first year, $15 in the second and $8 in the third, the bulb was initially selling for $50–$60 (without rebates) as of July 2012. As of March, 2013 Home Depot began offering the bulbs for $15 in stores.[8] Many stores sold out, and according to Philips customer service the L-prize bulb has been discontinued.

Technology[edit]

The winning bulb is able to achieve all of the required specifications by using red and blue LEDs that excite yellow phosphors which emits the required color of light. This is in contrast to most other led lights which use white LEDs to emit light that lacks all of the required characteristics for the L-Prize.

L Prize winning bulb on the right and its technological precursor on the left
Philips 60 W Incandescent Replacement bulb
DOE testing Consumer labeling
93.4 lm/W 94 lm/W
9.7 watts 10 watts
910 lumens 940 lumens
97.1% lumen maintenance at 25,000-hours (95% confidence)
93 CRI 92 CRI
2727 K CCT 2700 K

Future[edit]

PAR 38 floodlight[edit]

The rules for the PAR 38 lightbulb competition were retooled in July, 2012. The main specifications are still the same and the $5 million prize still remains open for the taking.

21st Century Lamp[edit]

On August 1, 2011, Cree announced that they had created a bulb that would exceed the DOE specifications for a 21st-century lamp. It emitted 1,300 lumens at 152 lumens per watt with a CRI of 91.2 and a color temperature of 2800 K.[9] They also stated at the time that they would not be bringing the bulb to market. As of March, 2013 they had not brought the bulb or any bulb like it to market.

References[edit]

External links[edit]