光学元件表面疵病检测仪的精度建模及预测

Precision Modeling and Prediction of the Defect Detector for Optical Element Surface

为了对疵病检测仪的精度进行预测并对设计方案的合理性进行验证,基于多体系统理论对疵病检测仪机械运动机构进行了精度建模。用低序体阵列和拓扑结构描述了疵病检测仪的结构特点,提出了疵病检测仪的精度模型,针对光学系统的要求进行了误差分离。基于该精度模型,以典型光学元件为例提出了误差补偿的计算流程,对疵病检测仪的精度进行预测。预测结果表明,光学探头的成像点与待测点沿光学探头光轴方向误差最大值为3.0μm,满足光学探头景深20μm的检测要求,同时光学探头成像点与光学元件待测点垂直于光轴方向误差及光学探头光轴与光学元件待测点处表面法向的夹角均在设计指标内。

In order to predict the precision of the defect detector and certificate its design proposal,the precision model of mechanical motion mechanism was established based on multi-body system theory. The low-order array and the topology structure were used to describe the design feature of the defect detector. The precision model was established,and the error was detached in order to meet the requirements of optical system. Based on the precision model,a calculated process of error compensation was put forward to predict the precision of the defect detector based on a typical optical element. The results showed that the maximum error between measuring point and imaging point along the optical axis of optical probe is 3.0μm,which can satisfy the demand of 20μm depth of focus. Meanwhile,the error between measuring point and imaging point normal to the optical axis and the angle between the optical axis and normal of surface at the measuring point are within design index.