TM-21-11 (Projecting Long Term Lumen Maintenance of LED Light Sources) published on July 25, 2011, this specification mainly predicts the performance and life of LED light sources, and is in line with the recently announced LM-80-08 LED The lumen maintenance rate experiment is linked, and the experimental data of LM-80-08 is used to estimate the long-term life performance of LED components and lamps/bulbs.
1. Use TM-21 to estimate the life of LED lamps
In order to make the LED industry have a clearer concept of TM-21 and understand how to make good use of TM-21 to estimate LED products, the author will explain the application and estimation of LM-80-08 and TM-21-11 in four procedures. Way:
Step 1: The LED component supplier conducts LM-80-08 experiments at 3 temperatures (55°C/85°C/optional temperature) for at least 6,000 hours on its LED Source (Package/Array/Module).
Number of samples required: (It is related to the estimated time)
Test time requirements: (connected with estimation accuracy)
At least 6,000 hours, 10,000 hours is recommended, and the test LED light decay data needs to be obtained every 1,000 hours. The shorter the interval (eg 500 hours), the more accurate the estimation time can be.
Step 2: Estimate the long-term life data of 3 test temperatures (55℃/85℃/optional temperature) according to the TM-21-11 formula.
Step 3: Obtain the In Situ Temperature of the LED element placed in the LED lamp.
Please refer to the ISTMT (In Situ Temperature Measurement Test) test program to obtain the temperature of the LED component placed in the LED lamp. The test temperature position must be the same as the Ts setting position of the LM-80-08. Temperature Measurement Point).
Step 4: Interpolate the calculated results of the measured TMPLED and TM-21 to obtain the estimated lifetime value of the TMPLED.
From the three test temperature points, the nearest two temperature points covering the TMPLED are selected as the calculation reference points.
Calculate Arrhenius Model temperature acceleration parameter A and obtain Decay Rate:α and fixed value parameter B0.
Calculate the L70 value of TMPLED with the above formula, and the same formula expresses the result of TMPLED.