LED blue light hazard rating and measurement standards
The LED blue light hazard examines the photochemical damage that blue light produces on the retina. In practical applications, people may look at different areas of the light source or the illuminating surface of the luminaire from different angles. Therefore, in order to meet various applications, IEC 62471 stipulates that the blue light hazard should be classified according to the exposure value (weighted irradiance and weighted radiance) in the direction of maximum radiation intensity of the maximum luminance region of the light-emitting surface. LED blue light hazard measurement and evaluation standards mainly include IEC/TR 62778 and IEC 62471, IEC 62471-2, GB/T 20145-2006, etc. IEC60598-1 adopts IEC/TR 62778 "Application of IEC 62471 for the assessment of blue Light hazard to light sources and luminaires". IEC/TR 62778 is based on IEC 62471 and simplifies the measurement of the blue light hazard of light sources and luminaires.
1) Measurement of LED light source
The light source is mounted on a five-dimensional position adjustment system. After determining the maximum exposure position of brightness and radiance, the system can sequentially align the light source with the measuring device, and test the brightness, radiance, and spectral data of the light source to be automatically calculated. The blue light hazard-weighted radiance LB and Ethr, and the blue light hazard classification of the light source according to the flow shown in FIG.
Figure 1 Blu-ray hazard assessment process (quoted from standard IEC/TR 62778)
2) Measurement of LED lamps
If the hazard information of the light source is known, the luminaire manufacturer can classify the luminaire according to the data provided in Fig. 1 according to the data provided by the luminaire. If the light source installed in the luminaire falls in the Ethr for RG2 category or is a small light source, the system can also be used to measure its minimum safe use distance dmin.
If the source information is unknown, the luminaire manufacturer can also use the system to measure the brightness, radiance and spectral information of the luminaire, and classify the blue light hazard of the luminaire according to the requirements of IEC 62471 or IEC/TR 62778. At this time, the conditions of the brightness measurement should be as consistent as possible with the actual application conditions, including the operating conditions of the luminaire, the test distance, the measurement field of view, etc., in order to effectively classify the luminaire.
Figure 2 shows the comprehensive test system for the blue light hazard of the light source and the luminaire. The system integrates a high-precision imaging luminance meter and a high-precision spectral radiometer to accurately achieve the hazard-weighted radiance, brightness, and hazard-weighted irradiance of the light source and the luminaire. Measurement of illuminance, spectrum, KB, V and Ethr parameters.
Figure 2 IEC/EN 62471 Blu-ray Hazard Measurement System
The system is highly expandable, and can flexibly configure various measuring instruments, test a full set of photobiohazard parameters required by IEC62471, and classify the measured light source or luminaire to meet the requirements of multiple measurement requirements, such as certification experiments. A manufacturer of lamps and lanterns with a wide range of products. In addition, the system can also pass the IEC 62471 and IEC/TR 62778 standard comparison tests to help manufacturers to confirm the true hazard level of the lamps according to the actual application.
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