TM21 calculator          
TM21 calculator, which helps calculate L70, L90 data
based on LM80 report. For customers who need L70B10, L70B20, L70B50,
L80B10, L80B20, L80B50, L90B10, L90B20, L90B50 data on our LED Module,
led PCB board, please feel free to contact us!
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What is the difference between the LED lamp life test L70/L80/L90 report?
L defines the percentage of lumens compared to the initial lumens.
It means that the ratio operation is performed with the luminous flux of the lamp that has worked for a period of time and the initial luminous flux of the lamp. L70 means that the luminous flux has attenuated to 70% of the initial luminous flux, L80 means that it has attenuated to 80% of the original, and L90 means that it has attenuated to 90% of the original.
The B value represents the fault data at the L data.
B10 means that 10% of the LEDs cannot meet the requirements.
Therefore, the LB value represents the actual life of a certain hour.
L/B is the standard definition of lamp life
For example, 50000h (L90/B10), that is, the time taken for 10% of the product's luminous flux output to drop below 90% of the initial value is 50,000 hours.
Conversely, it means that LED products have a reliability of 90% of the products' light decay less than 10% after working for 50,000 hours.

TM-21: It is mainly to calculate the life of the whole lamp by combining the LM80 report and the ISTMT report.
TM21 provides the processing method for the data measured by LM80, which mainly includes the following contents:
a. The data fitting method in the form of exponential function is given.
b. The correction method of the fitting life (70% light decay life) is given.
c. The detailed expression method of life is given.

d. The interpolation method for calculating the life at a given point temperature is given.

ISTMT stands for In Situ Temperature Measurement Test, which is the measurement of the temperature of the LED source box in the LED system (lamp or lamp). Simply put, it is the temperature of the LED inside the lamp. Measurements must be made at the temperature measurement point (TMP) as indicated by the LED package manufacturer.
The ISTMT report is the temperature rise test report.

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