Title: Multi-axis grating encoders for stage motion measurement

Authors: WooJae Kim; Akihide Kimura; Koji Hosono; Yuki Shimizu; Wei Gao

Addresses: Department of Nanomechanics, School of Engineering, Tohoku University, 6-6 Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan. ' Department of Nanomechanics, School of Engineering, Tohoku University, 6-6 Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan. ' Department of Nanomechanics, School of Engineering, Tohoku University, 6-6 Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan. ' Department of Nanomechanics, School of Engineering, Tohoku University, 6-6 Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan. ' Department of Nanomechanics, School of Engineering, Tohoku University, 6-6 Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan

Abstract: This paper describes an overview of the multi-axis grating encoders developed for measurement of stage motions. Two grating mirrors are employed in the grating encoders. One of the grating mirrors is utilised as the scale grating. The other grating mirror is included in the sensor head as the reference grating. The ±1st order diffracted beams from the two grating mirrors are superimposed to generate interference signals, which have information about not only the Z-directional out-of-plane displacement but also X- or Y-directional in-plane displacement. A prototype two-axis linear grating encoder with a software compensation technique for X- and Z-directional measurement, and a prototype three-axis surface grating encoder with a double Y-PD unit design for X-, Y- and Z-directional measurement are then presented.

Keywords: dimensional metrology; grating encoders; linear encoders; surface encoders; optical sensors; multi-axis displacement; multi-axis encoders; stage motion measurement.

DOI: 10.1504/IJNM.2011.043684

International Journal of Nanomanufacturing, 2011 Vol.7 No.5/6, pp.409 - 426

Available online: 11 Nov 2011 *

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