Design and construction of a two-degree-of-freedom linear encoder for nanometric measurement of stage position and straightness

Akihide Kimura, Wei Gao, Yoshikazu Arai, Zeng Lijiang

Research output: Contribution to journalArticlepeer-review

86 Citations (Scopus)

Abstract

This paper presents a two-degree-of-freedom (two-DOF) linear encoder which can measure the position along the moving axis (X-axis) and the straightness along the axis vertical to the moving axis (Z-axis) of a precision linear stage simultaneously. The two-DOF linear encoder is composed of a reflective-type scale grating and an optical sensor head. A reference grating, which is identical to the scale grating except the scale length, is employed in the optical sensor head. Positive and negative first-order diffracted beams from the two gratings are superposed with each other in the optical sensor head to generate interference signals. The optical configuration is arranged in such a way that the direction of displacement in each axis can also be detected. A prototype two-DOF linear encoder is designed and constructed. The size of the optical sensor head is about 50 mm (X) × 50 mm (Y) × 30 mm (Z) and the pitch of the grating is 1.6 μm. It has been confirmed that the prototype two-DOF linear encoder has sub-nanometer resolutions in both the X- and Z-axes.

Original languageEnglish
Pages (from-to)145-155
Number of pages11
JournalPrecision Engineering
Volume34
Issue number1
DOIs
Publication statusPublished - 2010 Jan 1

Keywords

  • Linear encoder
  • Measurement
  • Position
  • Straightness
  • Two-degree-of-freedom displacement

ASJC Scopus subject areas

  • Engineering(all)

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