基于补偿法的均匀照明自由曲面LED反光杯设计

根据面向理想光源的设计原理,提出了基于能量补偿和坐标迭代的自由曲面母线求解方法。在二维坐标系中建立系统模型,由反光杯反射光对直射投射光进行补偿,将反光杯右上边缘的光线反射到目标面左边缘,且随着光线下移反射光线逼近目标中心。根据Snell定律,以上边缘点为初始点,逐一迭代得母线上各点坐标,旋转或拉伸生成所求反光杯。在Tracepro软件中的模拟结果表明对圆形或正方形目标照度均匀性均优于85%,且系统能量利用率仅由LED出光角度和反光杯反射系数决定,该结构可使LED光源用于大范围照明。

Design of freeform surface LED reflectors for uniform illumination based on compensation method

According to the design principle of ideal light source,a method to obtain freeform surface generatrix based on energy compensation and coordinate iteration was proposed.Freeform surface LED reflectors for uniform illumination were designed.Firstly,the geometrical model of illumination system was established in two-dimensional coordinate system,in order to get uniform illumination.The directly incident energies were compensated by the reflected rays.Concretely,the rays were refected into the upper verge of the reflector to the verge area of the target plane,and go down to the bottom of the reflector along with the rays,approaching the middle of the target plane.Based on Snell equation and geometrical relation,choosing the point on the top of freeform surface generator as the initial point,the coordinates of all points on the freeform surface generator were obtained by iteration method,which could be rotated or extended into the freeform surface.The simulations of the designed LED reflectors with Tracepro software show that the illumination uniformity of either the circle or the square target plane is higher than 85%,and the energy efficiency which was affected only by the LED′s emitting angle and the reflectivity of the reflector surface can be high.These peculiarity enable LED light source to be applied in wide range lighting system.