A test method for quickly evaluating the life of LED lighting products

Attenuation of luminous flux is a key indicator to judge the life of LED. American Energy Star (ES) defines the light flux maintenance rate of LED lighting products below 70% as the end of life of LED lighting products. ENERGY STAR proposed to measure the 6000-hour luminous flux maintenance rate at 25℃ 1℃ and infer the life of LED lighting products (the 6000-hour luminous flux maintenance rate is not less than 91.8%). Compared with the development of LED lighting technology and the speed of product upgrading, the testing time of 6000 hours (or more) is still too long to meet the requirements of rapid industrial development.

Developing a fast reliability test method for life assessment of LED lighting products has become a crucial issue for the industry. In order to solve this problem, the State Key Laboratory of Semiconductor Lighting Joint Innovation has developed the Test Method of Accelerated Attenuation of Luminous Output of CSA020 LED Lighting Products after two years of research.

On August 9th, 2013, Fan Xuejun, a DOE reliability research expert, gave an in-depth and systematic explanation on the principle of the accelerated attenuation test method of luminous flux output, the verified test data and the significance of the release of this standard.

CSA020, based on the test methods of ENERGY STAR, LM-79, LM-80H and TM-21, and according to the theoretical basis of "E-Index Model", "Arrhenius Acceleration Model" and "Poisson Distribution", puts forward a brand-new accelerated attenuation test method: further shortening the test time by increasing the ambient temperature during the test (to increase the junction temperature of LED). Under the test condition that the maximum temperature is suggested to be 55℃, the data within 2000 hours can be used to replace the data of 6000 hours at room temperature required by ES method. This method not only greatly shortens the traditional test time of 6000 hours to less than 2000 hours, but also maintains the quality and accuracy of ES method. Fan Xuejun said that the feasibility and rationality of the accelerated attenuation test method adopted in this standard were not only proved theoretically, but also verified by the actual test data of LED lighting fixtures.

At present, CSA020 has been discussed in more than 400 member units of the National Semiconductor Lighting Engineering R&D and Industry Alliance, and the opinions of a wide range of enterprises in the industry have been solicited. More than 80 formal member units voted for it, and it was officially released, and gradually popularized and applied in domestic testing institutions. As a test method to quickly judge the life of LED lighting products, it will better support the implementation of relevant policies of state financial subsidies, and will certainly play a huge role in promoting the R&D and industrial development of LED lighting products.