Born in the USA: Philips’ L-Prize LED bulb

This article first appeared in EDN’s PowerSource blog.

Readers had a lively discussion in the comments that accompanied last week’s post on Philips winning the $10M L Prize. The L Prize is for the first LED bulb to be a functional, dimmable replacement for a 60W incandescent bulb. It’s sponsored by the Department of Energy and, of course, funded with US tax dollars. Considering that virtually all CFL bulbs, which contain a similar amount of complex control electronics, are manufactured in Asia, readers wanted to know: Where will the L Prize bulbs be made? And must the winning company be a US company? In addition, several readers also expressed doubts about the lifetime that could be expected for such a complex design.

The L Prize eligibility requirements (pdf) stated: "The entity [submitting the entry] shall be incorporated in and maintain a primary place of business in the United States." Philips Lighting North America certainly qualifies: It’s incorporated in the US and has 7,000 employees in the United States working in 25 factories spread across the US. It is the largest lighting manufacturer in the US.

But what about the development of the bulb, and where will it be manufactured? Zia Eftekhar, CEO of Philips Lighting North America, wanted to set the record straight: He told me the L Prize bulb “..was conceived, designed, and will be manufactured in the United States. The three design centers that had the major roles in its development are the San Jose Lumileds facility, our Lighting Systems and Control facility in Rosemont IL, and our  Color Kinetics facility in Burlington MA. The genesis of the project, the samples and the commercial production – all were developed in and will take place in the United States.” He repeated this for emphasis: “The origins and development of this product, as well as its future manufacturing are all in the United States. And of course this is fueling a lot of [follow-on] research and development. In addition, we have publicly said we will use the L Prize money to expand the manufacturing of this product in the United States. We will do this internally [at Philips facilities] as well as with American partners.”

Eftekhar said that a side benefit of the L Prize in setting consumer expectations is the amount of objective, thorough testing of lighting performance and lifetime the bulbs have undergone. It’s often pointed out that LED lights are handicapped by the bad experiences that consumers had with early CFLs which had poor performance and often failed well before their advertised lifetimes. The L Prize included criteria for both initial efficacy, color quality, and performance as well lumen maintenance (performance over time). Here are the test results for the Philips bulb:

1)      Photometric (LM-79 testing): From the 2,000 bulbs submitted by Philips, 200 were selected at random and sent to two DOE-approved independent testing labs for testing. Below are the requirements, and the Philips bulbs results which all exceeded requirements;

 

2)      Lumen Maintenance Testing: Once photometric testing was complete, the same 200 bulbs were installed in a lumen maintenance test apparatus in which ambient temperature was maintained at 45°C (113F) to simulate the elevated temperatures common in enclosed lighting fixtures. The bulbs were operated continuously. A movable integrating sphere took spectral measurements on each bulb every 100 hours for the first 3,000 hours of operation and every 168 hours (weekly) thereafter. Data for the first 7,000 hours of operation were used to predict tlumen maintenance of the laps at 25,000 hours. With 95% confidence lumen maintenance is predicted to be 99.3% at 25,000 hours, significantly exceeding the 70% L Prize requirement.