Have you heard of the Department of Energy’s “L” prize?
Washington, D.C. – The U.S. Department of Energy today announced that Philips Lighting North America has won the 60-watt replacement bulb category of the Bright Tomorrow Lighting Prize (L Prize) competition. The Department of Energy’s L Prize challenged the lighting industry to develop high performance, energy-saving replacements for conventional light bulbs that will save American consumers and businesses money.
Yep, you read that blurb correctly. Our very broke Federal Government handed Phillips Lighting North America (a subsidiary of Royal Philips Electronics of the Netherlands) a cool $10 million for developing a LED light bulb with the equivalent light output of a 60 watt incandescent.
The DOE press release goes on to discuss the performance of Phillips new LED bulbs’ performance with respect to its lifetime hours, performance at temperature extremes, performance in humidity. One aspect the DOE’s press release does not cover is light quality. This is because the ‘harsh’ and slightly blueish light emitted from LED’s that are great for the piercing daytime running lights used on newer cars create unpleasing lighting in your living room.
The reason LED lighting in a home, or any interior application, is unpleasing is because LED light is monochromatic, meaning an LED only emits a narrow wavelength of light (color). Unlike a traditional incandescent bulb that emits a true white light (made up of the entire visible spectrum of light) a white LED is either a combination of red, green and blue LED’s or a blue LED coated with yellow phosphorus.
Did you know there is no such thing as a white LED chip? “White” LEDs (packaged devices) start with a blue LED chip, also referred to in the LED industry as a blue “pump”. Then a yellow-based phosphor is applied over the blue chip – refer back to Figure 1. This combination of colors makes use of a phenomenon known as metamerism which occurs when our eyes and brain perceive two different but complementary colors as “mixing” to “create” a third complementary color. When the blue light shines through the yellow phosphor it is down-converted into what we see as white light. Blue LED chip + yellow-based phosphor = white light.
This tricking of the eye into seeing white light creating the harshness and blueish tint of the light emitted from white LED’s. White light from incandescent bulbs don’t have this problem. I’ll let Bill Nye explain…
The DOE is handing out a $10 million prize to the electronics giant Phillips Co. for creating a light bulb consumers aren’t asking for and don’t want. And, when consumers do purchase them, they will be unhappy with the light provided.
One final point. If white LED’s can perform in an automotive application (vibration, environmental extremes, voltage fluctuations, humidity, life testing etc.) why is the DOE retesting the LED’s?
The winning Philips product excelled through rigorous short-term and long-term performance testing carried out by independent laboratories and field assessments conducted with utilities and other partners. The product also performed well through a series of stress tests, in which the product was subjected to extreme conditions such as high and low temperatures, humidity, vibration, high and low voltage, and various electrical waveform distortions. The Philips L Prize winning product was also required to have a useful lifetime of more than 25,000 hours, compared with 1,000 to 3,000 hours for the products these highly efficient bulbs are intended to replace.
Just wondering.

