Optical Lens Design And Application For Direct-Lit LED Lamps

With the rapid development of LED(Light-Emitting Diode) technology, the advantages of the LED light source, high luminous efficiency, high color rendering index, high reliability and low power consumption are well-known, and LED are widely used in the field of indoor and outdoor lighting and special lighting. The high quality lighting, high energy efficiency and low cost, these superiority make LED the main development direction and the critical factors replacing the traditional lighting and traditional special lighting. Aimed at addressing the problems of the optical lens for the mainstream lamps, such as LED panel light and LED back light, a new corresponding optical lens for LED lamps is designed. It improves the quality of the LED lighting and reduces the cost of production of lamps effectively.To solve the problems of high price of the ultra-thin LED panel light, high thickness and large quantity of LED for traditional direct-lit LED panel light, a double freeform-surface lens with large view angle for direct-lit LED panel light is designed. Based on the relationship between illumination and the light intensity, a lens with large view angle is designed. Particle swarm optimization algorithm is adopted to optimize the arrangement of LED light source module. The new direct-lit LED panel light by using a lens with large view angle greatly reduces the number of used LED and thickness and it greatly reduces the production cost of LED panel light.According to the requirements of the LED back light, a lens of the LED back light with high uniform illumination is designed. Based on the B-spline curve function, the differential equation of lens is calculated by combining Snell formula with the angle partition method, after that the genetic algorithm is used to optimize the lens. The method can make the LED back light achieving the effect of high uniform illumination and reduce material cost.Based on the law of conservation of energy and the mesh generation method,the freeform-surface large angle lens was designed to achieve a near-field uniform illumination of LED array, whose inner surface is elliptical, the outer is freeform-surface. According to the mapping relations established by the law of conservation of energy, the mesh generation of the light source and the target surface was realized. Then, the refraction law was combined with the iteration to solve the freeform-surface data points. We analyzed the influence of the short axis and long axis ratio of the elliptical inner surface on the lens Fresnel loss and uniform illumination. Through the feedback optimization method to optimize the LED array and redivide the grid, the light intensity superimposed part is weakened and the overall illumination uniformity is improved. The simulation results show that it effectively improves the luminous efficiency and illumination uniformity.