The determination of the illumination evaluation system and method has a decisive influence on the choice of illumination source and the illumination effect. For a long time, only the visual and dark visual evaluation systems have been used internationally. The facts show that the visual curve does not include all the visual cells of the human eye, especially the blue cone cells. The defect of the visual curve is reflected as follows: the brightness value measured by the bright visual curve does not represent the brightness visible to the human eye, and the visual effects of different people cannot be evaluated. In fact, people of different ages have different perceptions of light, and the spectral pass rate tends to decrease with age. For color-blind patients with a 1.5% share of the population, the visual curve does not accurately reflect their visual perception. For a long time, the intermediate visual curves were in a missing state. Lin Yandan introduced that the study of intermediate vision has triggered an important exploration to reduce the brightness of white light in road lighting. And this led to two key questions, as the brightness decreased, how much visual performance decreased? To what extent does the increase in S/P value and color rendering index compensate for the above reduction in visual efficacy? Many experiments have been done internationally on the exploration of these issues. The test results show that for the central target, especially the colored central target, the brightness is reduced and the visual effect is reduced; the metal halide lamp can achieve the brightness of the high-pressure sodium lamp with a light effect of 10 cd/m2 with a light effect of 2 cd/m2. The light effect of the metal halide lamp 0.1cd/m2 is close to the high-pressure sodium lamp 1cd/m2 for the color recognition; the brightness required for different light sources to achieve the same visual effect is different, and the metal halide lamp requires less brightness than the high-pressure sodium lamp. Connector 1.5Mm Pitch,Zh Connector,Zh Terminal,Pitch Connector YUEQING WEIMAI ELECTRONICS CO.,LTD , https://www.weimaiconn.com
Establishing an effective system of intermediate visual photometry has always been a topic of concern to the international lighting community. In 2010, the International Commission on Illumination (CIE) introduced the intermediate visual photometric recommendation system. It has brought challenges and impacts to lighting systems built on the basis of bright visual photometry, and has had a major impact on the development and application of LEDs as future light sources. Dr. Lin Yandan, associate professor of the Institute of Light Sources, Department of Light Sources and Lighting Engineering, School of Information, Fudan University, pointed out that “intermediate vision is an objective existence of photometric definition. The intermediate visual curve is a necessary complement to the perfect evaluation of light metrics. The intermediate vision covers road lighting. The full range." Industry insiders said that road lighting standards will surely enter the era of intermediate vision evaluation. “The new CIE-MES2 system (0.005-5cd/m2) is by far the most complete intermediate vision system.†Lin Yandan added, “But there is still a lot of research work to be done to improve the intermediate vision system.â€
So what impact does the intermediate vision evaluation system have on lighting applications for various light sources? When applying intermediate visual photometry, the background brightness and the S/P value derived from the spectral data of the source are required as the input quantity, and the S/P value is the ratio of the dark visual light output to the clear visual light output, and the S/P value of the light source. The higher the light efficiency in the intermediate visual design. Measuring with the intermediate vision system will change the luminosity output of the lamp, which in turn changes the level of light efficiency of the lamp. Intermediate visual photometry favors white light sources with high S/P values. LEDs are white light sources with higher S/P values ​​than traditional light sources. The introduction of intermediate visual evaluation systems provides LED manufacturers with optimized LED development based on low-brightness lighting applications. The foundation is expected to further pave the way for the application of white LEDs to the field of outdoor lighting .
Countries such as the United Kingdom and Italy have pointed out in the relevant regulations that when using a high color light source, the illumination can be reduced by one level when lighting the same level of road. Zhang Haijun, chairman of the Shanghai Lighting Society, specially suggested that the illuminance can be reduced by half after increasing the color rendering index (Ra ≥ 60) of the street lighting source as specified in British Standard BS5489-1:2003. However, it is necessary to pay attention to this requirement. The conditions of use - "lighting level on the road (pedestrians and cyclists)", it is still too early to extend this result to various road operations, and further research and experimentation is needed before a decision can be made.
The MES2 system is complementary to the intermediate visual luminosity, but it is not the entire content of intermediate vision. Various specific environmental factors need to be considered. “Intermediate visual assessment is a comprehensive system engineering. It is a comprehensive evaluation method of LED intermediate vision that needs to consider different visual tasks of pedestrians and drivers at the same time. It also needs to examine the comprehensive evaluation method of LED intermediate vision with multiple constraints of brightness, spectrum and environment. Lin Yandan concluded.