Lab Testing for Philips Entry

Lab Testing for Philips Entry

All L Prize entries go through an extensive laboratory testing process to ensure that winning products meet the competition’s stringent requirements in areas including exceptional efficacy, long life, form factor, and suitability for mass manufacturing. A Technical Review Committee (TRC) reviewed all reports, test results, findings, and documentation for the Philips entry, and determined that it met the requirements.

Short-Term Testing

In Spring 2010, the Philips 60W replacement entry completed the first stage of the evaluation process: photometric testing. More than 200 samples of the product were subjected to LM-79 procedures measuring luminous flux, intensity distribution, correlated color temperature and chromaticity, color rendering index, and power factor. Instrumentation used in the testing included an integrating sphere and goniophotometer. Testing was conducted at two CALiPER-qualified labs: Independent Testing Laboratories, Inc., in Boulder, Colorado, and OnSpeX/CSA International in Atlanta.

L Prize RequirementPhilips Result
(average for 200 units)*
Luminous flux (lumens, lm)> 900 lm910 lm
Wattage (W)≤ 10 W9.7 W
Efficacy (lm/W)> 90 lm/W93.4 lm/W
Correlated color temperature (CCT)2700-3000 K2727 K
Color rendering index (CRI)> 9093

*NOTE: TRC approval was based on a complete analysis of the distribution of values for each parameter, not just the average values.

Long-term testing of the L Prize entry was conducted
in a specially designed high-temperature test bed.

Long-Term Testing

In June 2010, the next stage of evaluation began: long-term lumen maintenance testing. The 200 samples were sent to Pacific Northwest National Laboratory to be tested in a new high-temperature testing apparatus specifically designed for the L Prize competition and built with assistance from Orb Optronix. The test bed was maintained at 45°C to simulate actual operating conditions and the lamps were operated continuously. A movable integrating sphere (light measurement device) took spectral measurements on each lamp 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 lumen maintenance of the lamps at 25,000 hours. With 95 percent confidence, lumen maintenance is predicted to be 99.3 percent at 25,000 hours. This significantly exceeds the 70 percent L Prize requirement.

L Prize RequirementPhilips Result
(95% confidence, 200 units)
Lumen maintenance at 25,000 hours70%99.3%
Color maintenance(change in color point as
measured on the CIE 1976 (u’,v’)diagram)
< 0.0040.0006

Philips L Prize entry lamps were subjected to multi-level stress testing alongside benchmark CFLs.

Stress Testing

Independent stress testing was conducted by Intertek Laboratories using a proprietary method called Failure Mode Verification Testing (FMVT). This stress testing consisted of a simultaneous combination of electrical, thermal, vibration, and humidity stresses which were increased over 14 stress levels. Tests were benchmarked against good-quality, commonly available 60W replacement compact fluorescent (CFL) lamps. Throughout the testing, photometric performance was conducted to assess any changes in performance as well as failures.

During 10 levels of increasing stressors, including extreme maximum and minimum temperatures, vibration, high and low voltage, high humidity, and various electric waveform distortions, two-thirds of the CFLs included in the tests failed, but none of the Philips L Prize lamps failed. The remaining CFLs failed upon additional incremental stressing, while the Philips L Prize lamps continued to operate.

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