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Xuntong specializes in testing services for electrical accessories, consumer electronics, lighting, wireless, toys and other products.
TM-21-11(Projecting LongTermLumenMaintenance of LED Light Sources) was published on July 25, 2011. This specification mainly predicts the performance and life of LED light sources. It is linked with the recently announced LM-80-08LED lumen maintenance experiment, and uses LM-80 -08 experimental data to estimate the long-term life performance of LED components and lamps/bulbs.
1. Steps to estimate the life of LED lamps using TM-21
In order to allow LED companies to have a clearer concept of TM-21 and understand how to make good use of TM-21 to estimate LED products, the author will use four procedures to explain the application and estimation methods of LM-80-08 and TM-21-11:
Step 1: The LED component supplier conducts LM-80-08 experiments on its LEDSource(Package/Array/Module) at 3 temperatures (55℃/85℃/optional temperature) for at least 6,000 hours.
Sample number requirements:(It is related to the deductible time)
Test time requirements:(Connected to estimation accuracy)
At least 6,000 hours, 10,000 hours is recommended. The LED light decay data for testing needs to be obtained every 1,000 hours. The shorter the interval (e.g., 500 hours), the accuracy of the estimation can be improved.
Step 2: Estimate long-term life data at three test temperatures (55℃/85℃/optional temperature) according to the TM-21-11 formula.
Step 3: Get the in-situ measured temperature (InSituTemperature) of the LED element placed in the LED lamp.
Please refer to the ISTMT(InSituTemperature Measurement Test) test program to obtain the temperature of the LED element placed in the LED lamp. The test temperature position must be the same as the Ts setting position of LM-80-08. The temperature data taken out is called TMPLED(LED TemperatureMeasurement Point).
Step 4: Perform interpolation calculation based on the measured TMPLED and TM-21 calculation results to obtain the estimated life value of the TMPLED.
The two closest temperature points covering TMPLED were selected from the three test temperature points as calculation reference points.
Calculate the temperature acceleration parameter A of the Arrhenius Model and obtain DecayRate:α and the constant value parameter B0.
Calculate the L70 value of TMPLED using the above formula, and the same program expresses the result of TMPLED.
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