Optimization of suitable led lens desi̇gn using heuristic algorithms

The increasing importance of energy efficiency has led to the adoption of more efficient products in the lighting industry. LEDs (Light Emitting Diodes) are actively used in all lighting areas due to their longevity, energy efficiency and eco-friendliness. Lighting is the application of light to make the environment and objects visible. The purpose of lighting is to use light according to the desired requirement. LEDs are point light sources by their structure. To achieve optimal lighting conditions, the rays emitted from the light source must be distributed according to the lighting purpose. In LEDs, the lighting purposes are achieved using secondary optical devices (lenses, reflectors, collimators, etc.). In this study, the aim is to efficiently design the lens, which is the most important of the secondary optical components. A free-form lens design suitable for the target lighting area has been prepared. Free-form lenses are a new technology used in lighting design. Compact, lightweight, and high-performance optical products can be designed by this technology. In the study, one of the free-form lens design methods, the Ray Mapping Method (RMM) was used. The task of the RMM is to create optical surfaces that redistribute the brightness distribution on the target surface. The RMM was implemented using the C# programming language without professional optical design software. The input surface is considered spherical in the RMM. In the software section of the developed ray mapping method, freeform lens data with a PMMA optical material, 60° light angle and target distance of 1000 mm were generated. The obtained X and Z axis data were rotated around the X axis to obtain the Y axis data. An optical simulation of the free-form lens, whose solid model was obtained, was performed. The multi-dimensional lens data obtained with the developed software was optimized for the target criteria to be most suitable for the environments in which they will be used with heuristic algorithms. In this study, heuristic algorithms such as Particle Swarm Optimization (PSO), Gravitational Search Algorithm (GSA) and Firefly Algorithm (FA) were used. The expected light distribution curves, point intensity diagrams, light angle, photometric efficiencies, and Unified Glare Rating (UGR) values of a lens designed with these optimization techniques were obtained and compared using the Zemax simulation software and the Visual Photometric Tool program. According to these comparisons, the light distribution curves are symmetric and wide-angled in all methods. In the spot density diagrams, it is observed that the majority of the 10 million rays traced using all methods reach the detector. The method that reached the most rays to the detector was the FA method with 95.833%. The methods that most closely approach the design target light angle are RMM and GSA, both with an angle of 60.2°. In the UGR comparison, it was observed that the values for all methods are within the standard values according to the DesignLights Consortium (DLC). In the comparison of maximum UGR, the smallest value of 14.0 was obtained using the GSA and FA methods.