提出了一种曲面LED阵列设计方法。根据光线叠加原理,将LED排列在自由曲面上,通过曲率控制LED的出光角度。基于LED曲面阵列离轴照度分布的解析式,引入了基于模拟退火的粒子群优化算法,设定约束条件,构建均匀度评价函数,优化了LED曲面阵列的数值模型。制作出实物光源进行照度测量与缺陷检测。理论模拟和实物检测结果均显示,倾斜角度为45°,目标面与发光面面积比值为1∶0.85和1∶4时,照度均匀度分别达到91.79%和98.4%。在皮革缺陷检测中的结果表明,采用LED曲面阵列光源可凸显特定缺陷,易于图像处理,能快速准确地识别缺陷。

A design method of curved light-emitting diode (LED) array is proposed. Based on the principle of light superposition, the LEDs are arranged on the free-form surface, and the LED light-emitting angle is controlled through curvature. Based on the analytical formula of off-axis illumination distribution of the LED curved array, a particle swarm optimization algorithm is introduced based on simulated annealing, the constraint conditions are set, a uniformity evaluation function is constructed, and the numerical model of LED curved array is optimized. A physical light source is produced for the illuminance measurement and the defect detection. Both the theoretical simulation and the real detection show that when the inclination angle is 45° and the ratios of the target surface area to the light-emitting surface area are 1∶0.85 and 1∶4,the illumination uniformity is 91.79% and 98.4%, respectively. The results for leather defect detection show that the proposed curved LED array light source can highlight specific defects, quickly and accurately identify defects, and is easy for image processing.