Advanced Luminance Modeling of Light Sources for Simulation and Computational Purposes of Lighting Parameters

Abstract

The last decade is the time of a very dynamic development of lighting technology. This development covers many areas that complement each other. The development of light sources, luminaires, measurement techniques and design methods make it necessary to develop new, effective tools to support the design and analysis of lighting equipment. In lighting technology, the most common analysis is made of such parameters as the illuminance, luminance distribution and discomfort glare, inseparable from the specificity of modern light sources. A characteristic feature of almost all of them is high luminance, on the level of 107- 108cd/m2. High luminance facilitates the design of very precise optical systems, but also it is strongly associated with the possibility of discomfort associated with glare. Current methods of glare analysis in simulation software are related to conversion to the average luminance value of the luminaire, saved as simplified light parameters in electronic files (IES, LDT or similar). Currently the calculations take place as a result of calculation ratio the value of luminous intensity in a given direction and the surface area of the dimension of the luminaires in the same direction. This can lead to a significant understatement of the luminance of the luminaire in any situation where luminous intensity comes from the heterogeneous luminance distribution on the surface of the luminaire. This situation most often occurs in luminaires with high-luminance light sources with a reflector system and in the case of multi-source luminaires with lenses - eg multi-LED luminaires. The paper presents advanced methods of luminance modelling of light sources developed as a result of digital measurements of luminance distributions. A comparative analysis of the accuracy of the simulation calculations of the analytical lighting fixture model will be presented. The results will be compared to the classic ray tracing methods used in currently used models.