Miniaturised optical encoder for ultra precision metrology systems

J. Carr, M. Y P Desmulliez, N. Weston, D. McKendrick, G. Cunningham, G. McFarland, W. Meredith, A. McKee, C. Langton

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)

Abstract

We report here on a novel high resolution optical encoder, which can be employed within ultra precision metrology systems. Microsystems techniques have been used to monolithically integrate the discrete components of an encoder onto a single compound semiconductor chip, thereby radically reducing the footprint and cost of assembly. Gratings manufactured at the wafer level by standard photo-lithography, allow for the simultaneous alignment of many devices in a single process step. This development coupled with a unique photodiode configuration not only significantly increases performance but also improves the alignment tolerances in both manufacture and set-up, which substantially reduces the required set-up time. The optical encoder chip has been successfully demonstrated under test conditions on a 4 µm pitch scale: alignment tolerances have been increased with DC to AC ratios of the order of 7:1 and signal-to-noise ratios greater than 40:1. © 2008 Elsevier Inc. All rights reserved.

Original languageEnglish
Pages (from-to)263-267
Number of pages5
JournalPrecision Engineering
Volume33
Issue number3
DOIs
Publication statusPublished - Jul 2009

Keywords

  • Metrology
  • Monolithic integration
  • Optical encoder

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