Wang Chen, Zhong Fenghe, Ellis Jonathan D
Department of Electrical and Computer Engineering, University of Rochester, Rochester, New York 14627, USA.
The Institute of Optics, University of Rochester, Rochester, New York 14627, USA.
Rev Sci Instrum. 2017 Sep;88(9):095109. doi: 10.1063/1.5002711.
Straightness error is a parasitic translation along a perpendicular direction to the primary displacement axis of a linear stage. The parasitic translations could be coupled into other primary displacement directions of a multi-axis platform. Hence, its measurement and compensation are critical in precision multi-axis metrology, calibration, and manufacturing. This paper presents a two-dimensional (2D) straightness measurement configuration based on 2D optical knife-edge sensing, which is simple, light-weight, compact, and easy to align. It applies a 2D optical knife-edge to manipulate the diffraction pattern sensed by a quadrant photodetector, whose output voltages could derive 2D straightness errors after a calibration process. This paper analyzes the physical model of the configuration and performs simulations and experiments to study the system sensitivity, measurement nonlinearity, and error sources. The results demonstrate that the proposed configuration has higher sensitivity and insensitive to beam's vibration, compared with the conventional configurations without using the knife-edge, and could achieve ±0.25 μm within a ±40 μm measurement range along a 40 mm primary axial motion.
直线度误差是指沿着直线运动平台主位移轴的垂直方向的寄生平移。这种寄生平移可能会耦合到多轴平台的其他主位移方向。因此，其测量和补偿在精密多轴计量、校准和制造中至关重要。本文提出了一种基于二维光学刀口传感的二维直线度测量配置，该配置简单、轻便、紧凑且易于对准。它应用二维光学刀口来操纵由象限光电探测器感测的衍射图案，在校准过程之后，其输出电压可以得出二维直线度误差。本文分析了该配置的物理模型，并进行了仿真和实验，以研究系统灵敏度、测量非线性和误差源。结果表明，与不使用刀口的传统配置相比，所提出的配置具有更高的灵敏度且对光束振动不敏感，并且在沿着40mm主轴向运动的±40μm测量范围内可以实现±0.25μm。
