According to reports, the life performance measurement and evaluation of traditional light sources have been standardized. Due to their short life and interchangeability, whether it is incandescent or energy-saving lamps, the replacement of the bulb will not affect the continued use of the lamp, so generally The life of traditional light source luminaires is not evaluated. However, LED lighting products have a long life, and it is obviously inappropriate to evaluate the life of the LEDs through long-term experiments. At the same time, there are many forms of LED lamps, and most of the LED lamp sources are not interchangeable, so the life of different LED lamps can only be determined by the relevant life evaluation.
At present, the use of accelerated experiments to predict the life of LED lighting products is a very important means, the main mechanism is to let the stress level of the device work higher than the actual stress experienced in normal use, effectively stimulate product exposure failure, thereby shortening The normal time of device failure caused by a specific failure mechanism. However, for LED luminaires, due to its complex structure, there are many factors that affect its life. For example, the life of the LED light source itself, the LED driver and the environment all affect the life of the luminaire. And because the technology is still improving, the life of LED lamps should be evaluated after the technology is relatively perfect. However, before the LED technology is relatively perfect, it is necessary to establish a scientific and applicable LED lamp life evaluation method and evaluation model.
In addition, the definition of the life of LED lamps is still open to question. Because LED luminaires are different from the characteristics of a single illuminant of a conventional light source, it is composed of a plurality of illuminants and emits light. There is a color difference between the illuminants, and changes in color temperature and color rendering should also be in the definition of lamp life. Under consideration. For example, after using a LED luminaire for a period of time, its lumen maintenance rate is still as high as 50% or its performance is still higher than 70% of the initial performance, but its color rendering may not meet the requirements of use, then according to actual use, The end of life of the luminaire should be assessed, but according to the definition given in the current National Semiconductor Lighting Engineering R&D and Industry Alliance Recommended Technical Specifications, the life of the luminaire is still not final and can be used. Zou Nianyu believes that when defining the life of an LED lamp, it is necessary not only to pay attention to the maintenance rate of the light, but also to consider the relevant indicators such as color temperature and color rendering.
Zou Nianyu said that many researchers at home and abroad are working on the development of new LED lamp life evaluation methods, but so far no convincing model of the whole lamp life evaluation has been established.
According to the DOE report, there is currently no very viable way to assess the life expectancy of luminaires in the industry. Despite improvements in current lumen maintenance testing and planning standards, drive life and system color maintenance are still difficult to quantify. The DOE report is intended to define existing standards and planning standards, and the analysis identifies existing deficiencies that define the performance of LED luminaires. The report pointed out that the main problem lies in the fact that the existing method uses lumen loss as the only elimination mechanism for LED luminaires, and there is no standardized evaluation method to solve component problems other than light sources.
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