GB/T 41423-2022: Calculation of Long-term Luminous Flux and Radiant Flux Maintenance of LED Packages
The "GB/T 41423-2022 Calculation of Long-term Luminous Flux and Radiant Flux Maintenance of LED Packages" document was proposed by the China Light Industry Federation and is under the jurisdiction of the National Technical Committee on Lighting Equipment Standardization (SAC/TC 224). The document was published on April 15, 2022, and implemented on November 1, 2022. It is equivalent to IEC 63013:2017 "LED Packages - Calculation of Long-term Luminous Flux and Radiant Flux Maintenance" and references international standards such as IEC 62504, ANSI/IES TM-21-19, and ANSI/IES LM-80-20. This article will provide a detailed analysis of the main content, testing methods, calculation procedures, and reporting requirements of the GB/T 41423-2022 standard, focusing on the application of standards such as IESNA LM-80, IESNA LM-84, TM-21, and TM-27 in luminous flux maintenance and aging life testing, to help LED package manufacturers, users, and quality supervision and inspection departments better understand and apply this standard. Yiming Technology, as a professional LED lighting testing equipment manufacturer, has developed the LEDLM-84PL Luminous Flux Maintenance and Aging Life Testing System based on a deep understanding of this standard, providing standardized testing solutions for enterprises.
I. Introduction of the Standard
The "GB/T 41423-2022 Calculation of Long-term Luminous Flux and Radiant Flux Maintenance of LED Packages" document was proposed by the China Light Industry Federation and is under the jurisdiction of the National Technical Committee on Lighting Equipment Standardization (SAC/TC 224). The document was published on April 15, 2022, and implemented on November 1, 2022. This standard is equivalent to IEC 63013:2017 "LED Packages - Calculation of Long-term Luminous Flux and Radiant Flux Maintenance" and references international standards such as IEC 62504, ANSI/IES TM-21-19, and ANSI/IES LM-80-20.
The formulation and implementation of this standard provide standardized methods and procedures for luminous flux maintenance testing and long-term maintenance calculation of LED packages, helping LED package manufacturers accurately assess the long-term performance of their products, providing a basis for users to select appropriate products, and also providing standardized testing methods for quality supervision and inspection departments.
II. Scope of the Standard
The standard specifies the testing procedures and conditions for luminous flux maintenance of LED packages, and also provides procedures and conditions (criteria) for calculating long-term luminous flux maintenance based on limited collected luminous flux maintenance test data. This standard also applies to the calculation of long-term maintenance of radiant flux and photon flux; it also applies to LED packages for general lighting and plant lighting.
The test data used in the calculation methods in the standard are collected according to the ANSI/IES LM-80-20 (IESNA LM-80) method. IESNA LM-80 is the standard method for luminous flux maintenance testing of LED light sources, providing the data collection foundation for aging life testing. The long-term maintenance calculation procedure is based on the exponential fit function in ANSI/IES TM-21-19 (TM-21), and the TM-21 standard provides methods for calculating long-term luminous flux maintenance from LM-80 test data. When the exponential fit function in ANSI/IES TM-21-19 is not applicable, another border function procedure is provided. Additionally, IESNA LM-84 standard applies to luminous flux maintenance testing of LED luminaires, while TM-27 standard provides methods for calculating long-term luminous flux maintenance of LED luminaires.
Testing methods, data collection, and sample quantities should collect luminous flux maintenance test data according to the methods specified in ANSI/IES LM-80-20 (IESNA LM-80); it is recommended to measure luminous flux at intervals of less than 1000h. The test period should not exceed 6000h. Luminous flux maintenance testing is the core content of aging life testing, and by long-term monitoring of luminous flux changes in LED packages, the long-term performance of products can be accurately assessed.
III. Luminous Flux Maintenance Calculation Methods
The calculation methods include: Exponential Fit Function (EFF) and Border Function (BF), where EFF should be used as the primary calculation method, and BF should be used only when α≤0 in EFF.
1. Exponential Fit Function (EFF)
As described in ANSI/IES TM-21-19 (TM-21), the EFF method is based on the assumption that after the early luminous flux decay pattern ends, a curve fitting function can be used to fit and extrapolate subsequent test data. The TM-21 standard is an important basis for luminous flux maintenance calculation, and when used together with IESNA LM-80, it can accurately assess the long-term performance of LED packages. The formula is as follows:
Φ(t) = Be(-αt)
Where:
- t: Operating time;
- Φ(t): Normalized average luminous flux output at time t;
- B: Calculation initialization constant derived from least squares curve fitting;
- α: Decay rate constant derived from least squares curve fitting.
The lumen maintenance life calculation formula is:
Lp = ln(100×B/p)/α
Where:
- Lp: Lumen maintenance life expressed in hours, where p is the percentage of remaining lumens to initial lumens.
- When α>0, the exponential fit curve will decay to zero, and Lp is positive; when α≤0, the exponential fit curve will increase over time, but Lp is negative, in which case the Border Function (BF) should be used for calculation.
2. Border Function (BF)
When α≤0 in the exponential fit function, it indicates that the test data does not follow an exponential decay pattern. In this case, the Border Function (BF) should be used for calculation. The border function provides another calculation method applicable when the exponential fit function is not applicable.
IV. Reporting Requirements
In the report, the calculated life is obtained entirely according to the above formula, while the reported life is limited to no more than 5.5 times the total test time. This limitation ensures the reliability of calculation results and avoids inaccurate results caused by excessive extrapolation.
The test report should include the following:
- Detailed information of test samples (model, specifications, quantity, etc.);
- Test conditions and environmental parameters;
- Test data collection methods and time intervals;
- Calculation method used (EFF or BF);
- Calculation parameters (B, α, etc.);
- Calculated life and reported life;
- Test period and total test time.
V. Yiming Technology Testing Solution
Hangzhou Yiming Technology Co., Ltd. has developed the LEDLM-84PL Luminous Flux Maintenance and Aging Life Testing System through interpretation and understanding of the GB/T 41423-2022 standard. This system provides a basis for enterprises to improve the calculation of long-term luminous flux maintenance of LED packages, and provides a standard basis for enterprises, users, and quality supervision and inspection departments for product quality control.
The LEDLM-84PL Luminous Flux Maintenance and Aging Life Testing System fully complies with the requirements of the GB/T 41423-2022 standard, can collect luminous flux maintenance test data according to IESNA LM-80 method, and calculate long-term maintenance based on TM-21 exponential fit function. The system also supports IESNA LM-84 and TM-27 standards, applicable to luminous flux maintenance testing and calculation of LED luminaires. The system has the following features:
- Strictly collect test data according to IESNA LM-80 standard to ensure accuracy of luminous flux maintenance testing;
- Support IESNA LM-84 standard, applicable to luminous flux maintenance testing of LED luminaires;
- Calculate long-term luminous flux maintenance based on TM-21 standard, supporting both Exponential Fit Function (EFF) and Border Function (BF) calculation methods;
- Support TM-27 standard, providing long-term luminous flux maintenance calculation function for LED luminaires;
- Automatically calculate lumen maintenance life, completing the complete aging life testing process;
- Generate test reports that meet standard requirements, including luminous flux maintenance and aging life testing data;
- Support multi-channel simultaneous testing to improve aging life testing efficiency.
VI. Summary
The GB/T 41423-2022 standard provides standardized methods and procedures for luminous flux maintenance testing and long-term maintenance calculation of LED packages, helping LED package manufacturers accurately assess the long-term performance of their products. The two calculation methods specified in the standard, Exponential Fit Function (EFF) and Border Function (BF), provide scientific basis for luminous flux maintenance calculation under different circumstances. This standard, combined with international standards such as IESNA LM-80, IESNA LM-84, TM-21, and TM-27, forms a complete standard system for luminous flux maintenance and aging life testing.
As a professional LED lighting testing equipment manufacturer, Yiming Technology deeply understands the importance of the GB/T 41423-2022 standard and has developed the LEDLM-84PL Luminous Flux Maintenance and Aging Life Testing System to provide standardized testing solutions for enterprises. This system fully complies with standard requirements and supports standards such as IESNA LM-80, IESNA LM-84, TM-21, and TM-27, helping enterprises accurately assess the luminous flux maintenance of LED packages and LED luminaires, complete the complete aging life testing process, providing reliable basis for product quality control and jointly promoting the standardized development of the LED package industry.
