Research On LED Illumination Uniformity Based On Particle Swarm Optimization Algorithm

With the development of the LED industry,the application of LEDs in the lighting field is also increasing.People's requirements for LED lamps have changed from lighting to comfort and health.Since a single LED cannot meet the needs of scene lighting,the multiple LED arrays is required.Since the light intensity distribution of the LED is similar to the Lambertian distribution,the light intensity distribution in the illumination area is not uniform.There will be glare or shadows,and human's eyes will produce visual fatigue or even myopia under such uneven light conditions for a long time.In this dissertation,an improved particle swarm algorithm is used to optimize the LED array,improve the uniformity of light and verify the effectiveness of the method through simulation and experiments.The following is the main research content of this article:1.the basic theory of LED and equivalent thermal resistance model.The principle of LED light emission and common basic concept of photometry were introduced in this article.Based on the theory of heat conduction,the thermal resistance model of a single LED and LED array was constructed.We've gotten the the relationship between LED pitch and LED junction temperature and the relationship between LED's input electric current and output light flux through simulation and experiments.Which provides the basis for the following light uniformity optimization and lighting design.2.Design of Particle Swarm Optimization Algorithm for LED light uniformity based on illumination constraint.By theoretical model of a single LED light source,the illumination model of the LED array is deduced.Then the expression of the total irradiance of the LED array is obtained on the target plane.The standard deviation of illuminance on the target plane is used as an evaluation function.And the average illuminance is used as constraints,an improved particle swarm optimization algorithm is used to optimize the LED position,and two other common position distributions are given.The above three position distributions are simulated by MATLAB to verify the feasibility of this method.3.Method to judge illumination uniformity based on HSI color space.The method of converting from RGB color space to HSI color space is given.The method of determining the uniformity of LED illumination based on the luminance component of HSI color space is designed.The feasibility of this method is verified by simulation and experiments.4.Example of designing LED lighting source.Integrating the relationship between the LED input current and the output luminous flux and the luminous efficiency above,a high-efficiency lamp is designed.According to the optimized spatial distribution of the LED lamp by the improved particle swarm algorithm.And the design method of lighting system space location layout of highly light uniformity.Finally,the effectiveness of the design was verified through experiments.In this dissertation,the light-heat characteristic curve of the LED is obtained through the experimental test and statistical analysis.By theoretical model of a single LED light source,the illumination model of the LED array is deduced.And an improved particle swarm optimization algorithm is used to optimize the position of the LED.The method of using light components in the HSI color space to reflect light uniformity is proposed.And an illumination system with high light efficiency and high illumination uniformity was designed.The effectiveness of this method was verified by experiments.The method of this dissertation provides reference for the design of indoor lighting system.