Hong Yifan, Sato Ryo, Shimizu Yuki, Matsukuma Hiraku, Gao Wei
Precision Nanometrology Laboratory, Department of Finemechanics, Tohoku University, Sendai 980-8579, Japan.
Division of Mechanical and Space Engineering, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Japan.
Sensors (Basel). 2022 Apr 14;22(8):3010. doi: 10.3390/s22083010.
This paper proposes a new optical configuration for a two-axis surface encoder that can measure the in-plane (-axis) and out-of-plane (-axis) displacements of a positioning stage. The two-axis surface encoder is composed of a scale grating and a sensor head. A transparent grating is employed in the sensor head for measurement of the -directional displacement of the scale grating based on the Fizeau-type measurement method; a reference beam reflected from the transparent grating and the zeroth-order diffracted beam from the scale grating are superimposed to generate an interference signal. A pair of prisms and a beam splitter are also employed in the sensor head, so that the positive and negative first-order diffracted beams can be superimposed over a long working distance to generate an interference signal for measurement of the -directional displacement of the scale grating. Focusing on the new, extended -directional measurement mechanism, proof-of-principle experiments were carried out to verify the feasibility of the proposed optical configuration for the surface encoder that can measure the uni-directional displacements of a scale grating along the - and -axis. Experimental results from the developed optical configuration demonstrated the achievement of a -directional measuring range of ±1.5 mm.
本文提出了一种用于双轴表面编码器的新型光学配置，该编码器可测量定位平台的平面内（x轴）和平面外（y轴）位移。双轴表面编码器由一个标尺光栅和一个传感头组成。传感头中采用了一个透明光栅，基于菲佐型测量方法来测量标尺光栅的x方向位移；从透明光栅反射的参考光束与标尺光栅的零阶衍射光束叠加，以产生干涉信号。传感头中还采用了一对棱镜和一个分束器，以便正、负一阶衍射光束能够在较长工作距离上叠加，从而产生用于测量标尺光栅y方向位移的干涉信号。针对新的、扩展的y方向测量机制，进行了原理验证实验，以验证所提出的用于表面编码器的光学配置测量标尺光栅沿x轴和y轴单向位移的可行性。所开发光学配置的实验结果表明，实现了±1.5 mm的y方向测量范围。
