IESNA-LM-80 for LED Lumen Maintenance Test

IESNA-LM-80 (Measuring Lumen Maintenance of LED Light sources) is an approved method by Lighting Engineering Association of North America (IESNA) for the third generation SSL products; it mentioned the measurement standard and method. The main purpose is that measure and records the LED lumen maintenance change along with time, in other word, it is applied to test LED aging life.

Compare with the traditional light source, theoretically LED life can reach to 50000 hours. So it is hard to test the LED life, because it is impossible to light up the LED till it dies, and it is also unworkable because there are so many different types and different power of LED, if the problem can not solve, it will become a big resistance to develop and push LED products. Considering the real situation, IESNA passed the LM-80-08 approved method, which provides the guidance and specification for measuring and recording LED lumen vs time, and calculate the life time of LED luminaires in the end. Also it solves an urgent problem for LED industry.

When we say LED lumen maintenance and LED aging life, we will talk about LM-80, TM-21, TM-82 and etc. so it is necessary to explain them. LM-80-08 put forward the measurement method and then obtains the data, TM-21 put forward the calculate method and then obtains the data. In those standards, they mentioned L70, L50, L30 And etc. that means the time to 70% lumen maintenance, time to 50% lumen maintenance and time to 30% lumen maintenance. From the data, we can find lumen changing along with the time. Generally speaking, time to 70% lumen maintenance will be defined as the LED life. According to LM-80, the test time should be no less than 6000h, and 10000h is recommended. And during the test, temperature is limited at three points, first one is 55℃,second one is 85℃,and the third one is depends on the manufacturer. And generally, the test report should includes the following information: number of LED light source test, description of LED light source, description of auxiliary device, operating cycle, ambient conditions including airflow, temperature and relative humidity, Drive current of the LED light source during lifetime test, Initial luminous flux and forward voltage at photometric measurement current, Lumen maintenance data for each individual LED light source along with median value, standard deviation, minimum and maximum lumen maintenance value for all of the LED light sources, Observation of LED light source failures including the failure conditions and time of failure, LED light source monitoring interval, Photometric measurement uncertainty, Chromaticity shift reported over the measurement time.

In order to adapt to the standard, Lisun developed the LPCE-2(LMS-9000A) high accuracy spectroradiometer and integrating sphere test system, this system not only meet the requirements of CIE, EN and lm-79 clause 9.1, and also meet the requirements of LM-80. Base on the normal function, Lisun’s engineer developed new software to meet the requirements of LM-80. So LPCE-2 has two software, one is to test the luminous flux, color temperature, color rending index, wavelength, spectrum, light efficiency and etc. the other is to test and record the data of lumen vs time, according to the data, we can generally predict the LED life. But the main function for this system is to test the photoelectric and colorimetric parameters of LED, so it is not a standard way to test LED life, the test result and test report can not regarded as the final evaluation. But along with the technology developing, LISUN push LEDLM-80PL LED aging and life test system into the market, this system is designed according to LM-80-08, TM-82, TM-21 and etc. so it is completely meet the relevant standards.

LEDLM-80PL is developed base on the mature system of LPCE-2 (LMS-9000A). In the hardware, LEDLM-80PL still adopts the high accuracy CCD spectroradiometer to keep the high precision. And the most important is the software, the software absorbs the essence of the LPCE – 2, and then combine Arrhenius model to build a newly reliable LED life predict software. Users will only need to test the lamp for hundreds of hours under certain temperature, then the software will calculate the time to 70% (50%, 30%) lumen maintenance at this temperature, it will greatly help to improve the test efficiency and the accuracy and reliability of LED lumen maintenance testing.

We have a lot of customers who bought the LPCE-2 spectroradiometer and integrating sphere system, like SGS Australia, World Testing Lab, TUV and etc. At the same time, lots of customers show their interesting in LEDLM-80PL lumen maintenance and life test system. The reason why we can win so many trust and support from the world famous companies is because we always practice the motto right product, right price and right service. From the feedback, Lisun enjoy good reputation in the world market. And we will always provide the high quality products and superior service to all of our customers.