高精度半导体激光打标机F-θ镜头设计

F-θ lens design for high-precision semiconductor laser marking machine

为保证半导体激光打标机F-θ镜头的扫描质量,实现系统像高与扫描角的线性变化,需对F-θ镜头给予一定的畸变量,并使其满足等晕条件。分析F-θ镜头工作原理及像差要求,根据1064 nm半导体激光打标机的光源成像要求选择合适的玻璃材料,合理分配每片透镜的光焦度,以保证等晕成像;根据F-θ镜头线性成像要求,计算系统总畸变量为1.6%,系统总畸变量为系统的实际桶形畸变与相对畸变量之和;在光学系统优化设计时,引入这两项优化参数,优化过程中观察系统成像变化情况。设计结果表明:系统MTF曲线接近衍射极限,F-θ镜头相对畸变小于0.36%,各视场均方根半径均小于艾里斑直径,并且整个系统70%的能量集中在直径为16μm的圆内,系统总畸变量为1.58%,满足设计指标要求。

In order to ensure the scanning quality of F-θlens for semiconductor laser marking machine and realize the linear change of the image height and the scanning angle,it is necessary to give a certain distortion to the F-θlens and satisfy the isoplanatic condition.Firstly,the working principle and aberration requirements of the F-θlens were analyzed,and the appropriate glass material was selected by the light source imaging requirements of 1064 nm semiconductor laser marking machine to reasonably distribute the focal power of each lens to ensure the isoplanatic imaging.Secondly,according to the linear imaging requirements of F-θlens,the total distortion of the system was 1.6%,which was the sum of the actual barrel distortion and the relative distortion.Finally,in the optimization design of the optical system,these two optimal parameters were introduced to observe the system imaging changes during the optimization process.The design results show that the system modulation transfer function(MTF)curve is closed to the diffraction limit,the relative distortion of the F-θlens is less than 0.36%,the root-mean-square(RMS)radius of each field of view(FOV)is smaller than the Airy disk diameter,and 70%energy of the whole system is concentrated in a circle with a diameter of 16μm,the total distortion of the system is 1.58%,which meets the requirements of design index.