1. Reduction of Crosstalk Errors in a Surface Encoder Having a Long Z -Directional Measuring Range.
- Author
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Hong, Yifan, Sato, Ryo, Shimizu, Yuki, Matsukuma, Hiraku, Shimizu, Hiroki, and Gao, Wei
- Subjects
- *
LASER beam measurement , *DISPLACEMENT (Mechanics) - Abstract
A modified two-axis surface encoder is proposed to separately measure both the in-plane displacement and the Z-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 X- and Y-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 Z-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. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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