High-resolution and wide range displacement measurement based on planar grating
High-resolution and wide range displacement measurement based on planar grating
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DOI：
10.1016/j.optcom.2017.03.012
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发表时间：
2017-12-01
影响因子：
2.4
通讯作者：
Tan, Jiubin
中科院分区：
文献类型：
--
作者：
Lin, Jie;Guan, Jian;Tan, Jiubin
现代制造系统和仪器对精密平移工作台的高/超精密运动测量提出了很高的要求。在这项工作中，我们介绍了一种具有纳米分辨率的宽范围三轴光栅编码器，它可以同时测量工作台的x、y和z轴平移运动。该编码器由周期为8克的反射式平面刻度光栅和光学读取头组成。在光学读取头中采用了除长度和宽度外与平面刻度光栅相同的平面参考光栅。平面标尺光栅的x方向和y方向的+/-1级衍射束与平面参考光栅的相应衍射束干涉，形成测量信号。两个平面光栅的x方向和y方向的+/-1阶衍射光束沿其原始入射路径传输，起到自准直衍射光束的作用。因此，该编码器的z轴测量范围得到了极大的提高。X轴和y轴的测量范围取决于平面刻度光栅的尺寸。为了使编码器更紧凑，引入了一个双光栅分束单元(DGBS)和两个衍射光学元件(DO)。实验结果表明，采用本实验室研制的80段电子数据分割卡，z向位移分辨率可达4 nm。(C)2017爱思唯尔B.V.保留所有权利。
High/ultra-precision motion measurements for precision translation stages are highly desired in modern manufacturing systems and instruments. In this work, we introduce a wide range three-axis grating encoder with nanometric resolution, which can measure the x-, y- and z-axial translational motions of a stage simultaneously. The grating encoder is composed of a reflective-type planar scale grating with a period of 8 gm and an optical reading head. A planar reference grating, which is the same as the planar scale grating except the length and width, is employed in the optical reading head. The x- and y-directional +/- 1st order diffractive beams of the planar scale grating interfere with the corresponding diffractive beams of the planar reference grating, forming the measurement signals. The x- and y-directional +/- 1st order diffractive beams of the two planar gratings propagate against their original incident path, working as the autocollimatic diffractive beams. Therefore, the z-axial measurement range of the proposed grating encoder is greatly enhanced. The x- and y-axial measurement ranges depend on the size of the planar scale grating. To make the grating encoder more compact, a double grating beam-splitting (DGBS) unit and two diffractive optical elements (DOEs) are introduced. The experimental results indicate that the z-axial displacement resolution is as high as 4 nm with an electronic data division card of 80 segments developed by our lab. (C) 2017 Elsevier B.V. All rights reserved.