Surface Encoders for a Mosaic Scale Grating
Koji Hosono, WooJae Kim, Akihide Kimura, Yuki Shimizu,
and Wei Gao
Nano-Metrology and Control Laboratory, Department of Nanomechanics, Tohoku University, 6-6-01 Aramaki Aza Aoba, Aoba-ku, Sendai 980-8579, Japan
The surface encoder we propose for simultaneously measuring XYZ-directional displacements consists of a XY-axis with a scale grating and an optical sensor head. The XY-axis scale grating size determines the surface encoder’s measurement range in plane – in the X and Y directions. The mosaic XY-axis scale grating we use to expand the measurement range in plane consists of multiple XY-axis scale gratings arranged in plane. We present two optical configurations for the mosaic XY-axis scale grating. To confirm our configurations’ effectiveness, we fabricated two prototypes that we tested in basic experiments using a mosaic single-axis scale grating.
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