LM-80 is a standard that defines how the luminous maintenance and colour shift of LED lamps

Semiconductor Solid Lighting (SSL) is a trend of future development, especially today, where global energy is becoming increasingly tense and the climate is deteriorating today. With the application of electronic integrated technology in LED products, the trend of miniaturization of LED lamps and can only be modularized can become increasingly obvious. More and more LED products have begun to enter the field of general lighting to replace traditional lighting fixtures. However, integrated LED lamps are different from the light source of traditional lamps, and we choose the LED lamps on the one hand because it is environmentally friendly and energy -saving; on the other hand, it is also the title of its “long life”.

This article mainly focuses on international standards IEC62722-2-1 and the United States TM-28. LED Optical Aging Test Instrument prediction method, and the national recommendation standard GB/T xxxxx -201x L “LED lamps are reliable for the national recommendation standards in my country. The LED lamps in the sexual test method “1000H luminous maintenance rate test and optical life verification method are introduced.

1. International standard IEC62722-2-1 LED lamp performance
For the performance standards for lamps, the International Electrician Commission (IEC) has released IEC62722-1: 2014 “Lighting Performance-Part 1: General Requirements” and IEC62722-2-1: 2014 “Lighting Performance-Part 2-1 Part 2: LED Lighting Private The two standards of special requirements. IEC62722-2-1 did not give the LED lamp life prediction method, but it was given the rated service life of the LED module used in the product information requirements.

In terms of LED lamps, IEC62722-2-1 stipulates that “IEC62717LED rice fast performance requirements are applicable to LED lamps”. The requirements of 10.2 clauses in IEC62717 are “25% rated life and less than or equal to 6000H operation time.
Luminance maintenance rate classification:

Luminance maintenance rate(%)	Code
≥90	9
≥80	8
≥70	7

In terms of the determination method of the luminance maintenance rate category, IEC62717 has the following regulations:
(1) Light the LED module, with stability, measure the output of the luminous light, and use it as the initial light output of the LED module;
(2) Measure the output of luminous light at 1000h at a interval, the test time is 25%rated life, and it is less than or equal to 6000H;
(3) Test the test results on the initial home;
(4) The definition of 6000H is maintained at which level in Table 1, and is represented by the corresponding code.

Advantages:
This method gives the LED lamps if the LED module defined by IEC62717 is maintained, which means that the LED module meets the requirements of IEC62717 and has a corresponding luminous maintenance rate category. The performance temperature of the module after lamps does not exceed the temperature during the test of the IEC62717 in the IEC62717. It can save costs and time.

Disadvantage:
(1) For the designer of the lamp, it is not enough to consider that only the LED module’s lumens maintaining the data at the TP temperature is not enough.
(2) The standard only gives the exponents of LED lamp life. For example, when LED lamps are gradually decayed by the light output, the life span is expressed in LXBY, but it is not given a method of predicting the LED lamps’ light liter life.

2. American LM-84 and TM-28 draft
The United States is drafting the LM-84 “Measurement of LED Lights, Light Engine and LED Lantern Landwater Streaming and Color Maintenance Methods” and TM-28 “Prediction of LED Lights and Lights for Long-term Lights” standard, which is different from the release of LM-80-08 that has been released with TM-21-11 standards, the two standards drafted are mainly targeted at end-application product LED lamps and LED lamps. It proposes two light prediction methods for LED lamps:
(1) Direct method
Similar to the LM-80 and TM-21 methods, this method is to use the LED lamps at least 6000H LM-84 data to predict the optical flux similar to the time range of the TM-21 method. Specific steps are as follows:
1) Rentification
The LM-84 test data is native to 0h.
2) Average
The average data on each test condition and the measuring point is average.
3) Select the fitting data
For example: data before 1000H cannot be used for curve fitting. For data with a test interval greater than 1000H, 50%of the data after the total test time will be used for curve fitting.
4) Adjust the number and results of the test sample
Depending on the number of test samples, the prediction results are adjusted, see Table below:
The relationship between the number of samples and forecast amplification X

Sample Quantity	X
3	3
4	4
5-6	5
7-10	5.5
10+	6

This method directly tests the most luminous maintenance rate of LED lamps, and uses the actual measured LED lamps output attenuation data over time to predict the life of the product light -pass maintenance rate. This data can directly reflect the light output characteristics of the LED lamp system, but at least 6000H The test cycle and large number of samples are also a lot of costs for enterprises.

(2) Overlapping method or combination method
This method also uses LM-84 data and LM-80 data at the same time, and requires at least 3000H LED lamps to maintain the test. Compared with the 6000H test time of the direct method, it can be reduced by half. Specific steps are as follows:
1) Rentification
The LM-84 test data is native to 0h.
2) Average
The average data on each test condition and the measuring point is average.
3) Selection of LM-80 data
The data before 1000H cannot be used for curve fitting. For data with a test interval greater than 1000H, 50%of the data after the total test time will be used for curve fitting.
4) Adjust the number and results of the test sample
According to the different number of sample samples, the prediction results are adjusted, as shown in Table 3.
The relationship between the number of samples and forecast amplification X

Sample Quantity	X
5	1.5
6	2
7	2.5
8	3
9	3.5
10	4
11	4.5
12	5
13-14	5.5
15+	6

This method uses LED module flow to maintain data and LED lamps. For example, 5 LED lamps samples, 3000H LM-84 lumens maintainence data, according to the number of test samples and predictive magnification, up to 15000h lumens to maintain data. For example, the stock of the LED lamps of 50000h is claimed that the number of samples is required at least 15, which also increases the burden on the lamp manufacturer.

LEDLM-80PL LED Lumen Maintenance and Aging Life Test System is designed according to IES-LM-80 and TM-21, it used to test & record the optical and electrical Maintenance for single LED or LED module, the software is based on Arrhenius model and TM-21 to calculate the LED life. The LEDLM-80PL needs to work with a GDJW/GW Series High Temperature Chamber and and DC12010 DC Power Source. Please click here to view the test report samples of LM-80 and TM-21.

LEDLM-84PL LED Lumen Maintenance and Aging Life Test System is designed according to IES LM-84 and TM-28, it used to test & record the optical and electrical Maintenance for LED luminaires, the software is based on Arrhenius model and TM-28 to calculate the LED life. The LEDLM-84PL needs to work with a GDJW/GW Series High Temperature Chamber and and LSP-1KVARC AC Power Source. Please click here to view the test report samples of LM-84 and TM-28.

LED has the feature of long life, but its life will be different with the different working condition and driver current. Generally the life will be around 50K hours. Different from the traditional lightsource, LED light will decay gradually rather than extinguish instantly. 
1) L70 (hour): time to 70% lumen maintenance
2) L50 (hour): time to 50% lumen maintenance

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