基于光斑跟踪系统的位敏传感器误差修正

Error corrections for position sensitive detector based on speckle tracking system

位置敏感探测器(PSD)测量误差主要来自于自身非线性、干扰和安装倾斜的影响,且PSD的直接测量范围受限于探测器的尺寸。针对这些问题,分析了自身非线性、干扰和安装倾斜的影响原理,根据测量值与实际值的线性关系,提出利用伺服模组与PSD相结合的光斑跟踪系统来进行局部拟合实时校准的方法减小干扰影响并消除PSD安装倾斜误差,利用线性度较好的中间区域减小自身非线性影响。实验以Al2O3/PEN为样品,利用研制的光斑跟踪系统对上述方法进行的验证结果显示,线性相关系数维持在1±0.001 5/40 mm之间,线性度标准误差减小到0.3μm/40 mm以下,最大误差在16μm/40 mm之内且测量范围也可增大到模组的行程200 mm,此方法简单有效、灵活实用,特别适用于光强度弱且多变和测试范围较大的场合。

The accuracy of position sensitive detector （PSD） is mainly affected by the non-linearity, interference and the installation tilt error, and the measurable range is limited by the size of the detector. Based on the analysis of the influencing mechanism of the non-linearity, the interference and the installation tilt error, a speckle tracking system was introduced to remove the influence by local fitting and real-time calibration according to the linear relationship between the actual value and the measured value. A12OJPEN sample was used to experimentally verify the designed spot tracking system platform. The results show that the linear correlation coefficient maintains in a range of 1_＋0.001 5, the linearity standard error is reduced to 0.3 txm/40 mm, the maximum error is less than 16 ixrn/40 mm and the measurable range can be increased to the stroke of the module, 200 mm in this work. This method is effective, flexible and practical for position detection applications especially under feeble light condition and for large measuring range.