Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5449012 | Optics Communications | 2017 | 7 Pages |
Abstract
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  μm 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.
Keywords
Related Topics
Physical Sciences and Engineering
Materials Science
Electronic, Optical and Magnetic Materials
Authors
Jie Lin, Jian Guan, Feng Wen, Jiubin Tan,