为了提高半导体激光加工中激光光斑中心定位精度, 根据皮秒超短脉冲激光辐照单晶硅后产生的光斑图像灰度分布特点, 提出了一种基于灰度直方图的激光光斑中心定位算法, 通过模拟激光光斑仿真分析和单晶硅刻蚀实验, 对比研究了不同辐照时间与不同激光功率条件下该算法与传统算法的定位精度。结果表明, 在辐照时间不同的条件下, 该算法定位精度达到0.761 μm, 比灰度重心法提高51.3%, 比最大行列灰度值法提高93.9%; 在激光功率不同条件下, 该算法的定位精度达到0.793 μm, 比灰度重心法提高73.4%, 比最大行列灰度值法提高86.8%。此研究可为皮秒超短脉冲激光光斑中心定位控制系统的设计提供指导。

In order to improve the location of laser spot center accuracy in semiconductor laser processing, according to the gray distribution characteristics of spot image generated after picosecond ultra-short pulse laser irradiating monocrystalline silicon, an algorithm of laser spot center location based on gray histogram was proposed. Through simulation analysis of laser spot and monocrystalline silicon etching experiment, the positioning accuracy of the proposed algorithm was compared with that of the traditional algorithm under different irradiation time and laser power. Results show that under different irradiation times, the algorithm precision is 0.761 μm, 51.3% higher than that of gray centroid method and 93.9% higher than that of the maximum column gray value method. Under different laser power, the algorithm precision is 0.793 μm, 73.4% higher than that of gray centroid method and 86.8% higher than that of the maximum column gray value method. It can provide guidance for the design of the control system for spot center positioning of picosecond ultra-short pulse laser.