L Prize Lumen Maintenance Report As part of the ongoing monitoring process for the L Prize, the DOE published “Lumen Maintenance Testing of the Philips 60-Watt Replacement Lamp L Prize Entry,” in August. This report documents 18,000 hours of lumen maintenance testing. This minimum test period, outlined in the competition brief, was achieved in April 2011.
Because length of lifetime is a key issue in making the case for one of the benefits of using LEDs, the DOE continues to run the lumen maintenance testing on the Philips entry.
According to the DOE, the testing process includes 200 samples that are being run continuously in a high-temperature (45 C, 113 F) test bed that simulates actual conditions. A movable, integrating sphere takes spectral readings of each lamp at regular intervals. After the first 7,000 hours of run time, lumen maintenance predicted with 95 percent confidence was found to be 97.1 percent at 25,000 hours, higher than the L Prize lumen maintenance requirement of 70 percent (L70). In July, after the 18,000-hour mark was passed, the projected lumen maintenance was 97.8 percent at 25,000 hours. Additionally, there was very little change to overall light output, and chromaticity levels remained well within the L Prize criteria. Further details about the entire L Prize testing process can be found at lightingprize.org.
CALiPER Testing The DOE has completed four more rounds of product testing through its CALiPER (Commercially Available LED Product Evaluation and Reporting) program.
Round 14, completed in March, examined LED downlight retrofit units. Eleven samples were evaluated in a downlight housing rated for 6-inch insulation contact (IC) and mounted in a 24-by-24-inch insulated enclosure. The summary report includes photometric performance results and compares the findings to equivalent luminaires using conventional lamps.
Round 15, completed in May, tested 10 LED floodlights that represent the functionality of an equivalent range of conventional floodlight luminaires. The findings suggested that there are still areas in which LED floodlights can be improved.
Completed in July, Round 16 looked at 13 LED products labeled as BR30 or R30 (spot and flood reflector) lamps. Testing showed significant improvements over earlier generations of LED BR30 and R30 lamps. However, the summary report did indicate that there is still a need for more selection within this LED lamp category, both in terms of lumen output and distribution type.
The latest round of testing—Round 17, completed in August—focused on six LED AR111 lamps. The summary report indicated that this niche lamp category is not as far along as some other directional LED lamp types. At present, LED AR111 offerings are not competitive replacements for halogen AR111 lamps, particularly in terms of color quality and luminous intensity distributions. All of the summary reports can be downloaded at 1.usa.gov/wZ2qI4.
Research and Development Following its fourth annual SSL Manufacturing R&D Workshop, which took place in San Jose, Calif., on June 13 and 14, the DOE has published the 2012 report “Solid-State Lighting Research and Development: Manufacturing Roadmap.” This roadmap serves as a guide to the R&D program and assists in answering funding questions. The 2012 version includes a few important updates from the previous years, including most of the priority manufacturing task descriptions with status updates toward completion.
The DOE has also posted a summary report from the workshop along with all of the presentations (see link below). More than 200 individuals attended the most recent workshop where discussions focused on cost reductions, as opposed to price, of bringing LED technology to market. A PDF of the roadmap can be downloaded at 1.usa.gov/P2iJoN. The workshop report can be downloaded at 1.usa.gov/Q4BY2R.
In June, the DOE announced the selections for its third round of SSL manufacturing R&D funding opportunities. According to the DOE announcement, three two-year projects will concentrate “on achieving significant cost reductions while maintaining quality by improving manufacturing equipment, processes, or monitoring techniques.” The three recipients are Durham, N.C.–based Cree; Milpitas, Calif.–based KLA-Tencor; and Dexter, Mich.–based k-Space Associates.
Cree's project will focus on the development of an optimized LED fixture design, at low cost, for general illumination purposes both indoors and out. KLA-Tencor's initiative will focus on improving color consistency of LEDs using measurement tools during the manufacturing process to reduce fluctuations in LED quality. Finally, k-Space Associates is working to develop a more efficient manufacturing process for OLED layers. The project furthers the technical capabilities of its existing optical-monitoring technology, which enables high-precision measurements of OLED layers during mass production.
DOE support for the projects totals $7.1 million, and private-sector funding from the three companies will add another $5 million. Due to budgetary restrictions during fiscal year 2012, the DOE will not select or fund any projects in the SSL Core Technology or SSL Product Development categories. Full details on all of the DOE's SSL R&D initiatives can be found at 1.usa.gov/QnwEUc.