激光发散角测量的误差分析

摘要

为了研究产品装调过程中,套孔法和CCD成像法得到的激光发散角偏差较大原因,采用ZEMAX仿真进行了理论分析,并结合相关试验进行了验证。结果表明,在CCD白光观瞄系统中利用CCD成像法测量激光光斑大小时,由于白光与激光间存在光程差,计算激光发散角时,需要消除光程差导致的图像误差的影响。激光光斑大小与距离符合双曲线规律变化。近场条件下不成线性关系,CCD成像法测量得到的激光光斑图像偏大,计算得到的激光发散角远大于套孔法的测量值；远场条件下近似成线性关系,套孔法及CCD成像法测算得到的激光发散角数值基本一致。该研究可以根据产品的设计参量,消除光程差对激光激光束散角的影响,提高测量精度。%In the product delivery process, deviation between the laser divergence angled calculated by hole-set method and CCD imaging method is usually large. In order to find the reason, theoretical analysis was carried out by ZEMAX simulaiton and experimental verification was done. The results show that: when using CCD imaging method to measure the laser spot size in white CCD sighting system, due to optical path difference between white light and laser, the influence of image error caused by optical path difference on the calculation of laser divergence angle should be eliminated. Laser spot size and distance are in accordance with the law of hyperbolic variation. In the near field conditions, there is not the linear relationship. Laser spot image measured by CCD imaging method is large and the calculated laser divergence angle is far more than the angle measured by hole-set method. In the far field conditions, there is approximately the linear relationship. The values of laser divergence angles calculated by hole-set method and CCD imaging method are in consistence. The study can eliminate the influence of optical path difference on divergence angle of laser beam and improve the measurement accuracy according to design parameters of the products.