Yin Ziqiang, Chai Ning, Wang Sujuan, Huang Guangcan, Lin Jian, Zhao Rongli
Appl Opt. 2020 May 20;59(15):4718-4731. doi: 10.1364/AO.391512.
This study presents a new (to the best of our knowledge) error separation method with a single displacement probe, named as single probe shear scanning (SPSS) method, for the on-machine optical profile measurement to overcome the problems of the existing multiprobe method like the large deviation of probe spacing and the probes' performance difference. The confocal sensor with superior dynamic range, high lateral resolution, and large measurement angle to surface is applied in this study to fulfill the measurement of the optical aspheric surface. The single probe measurement system, in which the probe fixed on a flexure hinge is driven straight within a millimeter-level travel range, is established to realize the function of the multiprobe. For the established system, a new exact profile reconstruction algorithm is built to eliminate the influences of straightness errors of the scanning stage and the systemic errors of shear stage, and to reduce the effect of the sensor drift. The reconstruction algorithms by difference measurement with two shears are studied to build the bidirectional segment stitching reconstruction method, which reduces the error accumulation and improves the reconstruction accuracy under the condition of measuring errors. A profile reconstruction method with three shears measurement is proposed to make a further improvement on the reconstruction accuracy. The proposed reconstruction method with three shears measurement is successfully employed for the on-machine measurement of an aspheric surface profile, and the evaluation results agree well with those from the Taylor profiler.
据我们所知，本研究提出了一种新的误差分离方法——单探头剪切扫描（SPSS）方法，该方法使用单个位移探头进行在位光学轮廓测量，以克服现有多探头方法存在的诸如探头间距偏差大以及探头性能差异等问题。本研究采用了具有卓越动态范围、高横向分辨率以及大表面测量角度的共焦传感器来完成光学非球面的测量。建立了单探头测量系统，其中固定在柔性铰链上的探头在毫米级行程范围内直线驱动，以实现多探头的功能。针对所建立的系统，构建了一种新的精确轮廓重建算法，以消除扫描台直线度误差和剪切台系统误差的影响，并减少传感器漂移的影响。研究了通过两次剪切差分测量的重建算法，构建了双向段拼接重建方法，该方法在测量误差情况下减少了误差累积并提高了重建精度。提出了一种三次剪切测量的轮廓重建方法，以进一步提高重建精度。所提出的三次剪切测量重建方法成功应用于非球面轮廓的在位测量，评估结果与泰勒轮廓仪的结果吻合良好。
