Precision Nanometrology Laboratory, Department of Finemechanics, Tohoku University, Sendai 980-8579, Japan.
Division of Mechanical and Space Engineering, Graduate School of Engineering, Hokkaido University, Kita 13, Nishi 8, Kita-ku, Sapporo 060-8628, Japan.
Sensors (Basel). 2022 Dec 6;22(23):9563. doi: 10.3390/s22239563.
A modified two-axis surface encoder is proposed to separately measure both the in-plane displacement and the -directional out-of-plane displacement with minor crosstalk errors. The surface encoder is composed of a scale grating and a small-sized sensor head. In the modified surface encoder, the measurement laser beam from the sensor head is designed to be projected onto the scale grating at a right angle. For measurement of the - and -directional in-plane scale displacement, the positive and negative first-order diffracted beams from the scale grating are superimposed on each other in the sensor head, producing interference signals. On the other hand, the -directional out-of-plane scale displacement is measured based on the principle of a Michelson-type interferometer. To avoid the influence of reflection from the middle area of the transparent grating, which causes periodic crosstalk errors in the previous research, a specially fabricated transparent grating with a hole in the middle is employed in the newly designed optical system. A prototype sensor head is constructed, and basic performances of the modified surface encoder are tested by experiments.
提出了一种改进的双轴面编码器，可分别测量面内位移和方向的面外位移，且具有较小的串扰误差。该面编码器由一个标尺光栅和一个小型传感器头组成。在改进的面编码器中，传感器头的测量激光束被设计成以直角投射到标尺光栅上。为了测量和方向的面内尺度位移，来自标尺光栅的正、负一级衍射光束在传感器头中相互叠加，产生干涉信号。另一方面，方向的面外尺度位移是基于迈克尔逊型干涉仪的原理来测量的。为了避免中间区域反射引起的周期性串扰误差，这在以前的研究中是一个问题，新设计的光学系统采用了中间有孔的特制透明光栅。构建了一个原型传感器头，并通过实验测试了改进的面编码器的基本性能。
