Design Of LED Street Lamp Illumination System And Research Of Illumination Distribution Of LED Arrays

With its advantages of small size, long life, high electro-optic efficiency, environmental protection and energy saving, etc, it has become a trend that LED light source to replace the traditional lighting. In some illumination areas, such as street lighting, landscape lighting, display backlight, automobile headlamp lighting, indoor lighting and so on, LED light source has been a general and a wide applications. In the above applications, they often need a second optical design of the LED light source to receive a specific lighting effect. The optical design of the LED street lamp was studied in the paper, and aimed to design a free-form surface lens, a uniform rectangular lighting on the road was realized.The paper comprehensively used the previous optical device design method of the free-form surface, to establish a mathematical model that rays emitted from the LED light source were refracted through the free-form surface lens and reach the receiving surface, Snell law was used to establish a function between incident light vector, output light vector, and normal vector of the free-form surface. In the light transmission process, any point in the free-form surface corresponded to the unique point on the illuminating surface, and the free-form surface and illuminating surface were combined together to set up the Partial Differential Equations about the free-form surface in polar coordinates and directional derivative. After dividing the proper grid, Matlab was used to solve equations and the coordinates of a free surface were obtained. The coordinate file was rewrote for ibl format, and imported it into the3D modeling software of Pro/E, then the free-form surface lens of3D models was got, the paper used lighttools for illumination simulation analysis, the result showed that the rectangular distribution was got, and the energy efficiency was high, and the light was well-distributed. At last, illuminance distribution of LED arrays was researched, and a more appropriate space between LEDs was obtained, with advantages of less LEDs and getting a more appropriate illumination. Compared with the previous method using an optical design software to optimize for free surface, the paper used equation had so many advantages, for example, it cost less time, and for some complex system, the effect is particularly obvious. The method without optical software, and the results complied with the design requirements, so the method is widely applicable.The paper used the topological relationship between the receiving surface and the free-form surface to set up the Partial Differential Equations, theoretically, as long as building this topology relation, the coordinates of the free-form surface was got, then got the right lens, this method was widely applicable to LED light source, it can be used to design the road lamp, the reflector lamp in the car.etc, enriches the applicable scope of LED, and lays a foundation for LED light source to replace the traditional.