30 September 1994 New-type of pseudorandom position optical encoder with submicrometer resolution: design and characterization
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The characteristics of a new twin-track absolute position optical encoder are presented. One tract containing a pseudorandom code and the second a periodic pattern are synchronously engraved on a glass slab. The optical reading head design composed of a LED, a gradient index lens and a linear CCD array, with simple intensity-based signal processing to read the code pattern is described in detail. This design is combined with a standard Moire method to enhance resolution. Performance enhancement of the optical reading head is studied in terms of track illumination versus code density, detector geometry versus the lens point-spread function (Airy disk); and reduction of extrinsic spatial noise by the application of thick films. Each parameter was considered in terms of the optimal field of view and depth of field of the system.
© (1994) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Miroslav Durana, Ronald N. Miles, Philippe A. Robert, "New-type of pseudorandom position optical encoder with submicrometer resolution: design and characterization", Proc. SPIE 2263, Current Developments in Optical Design and Optical Engineering IV, (30 September 1994); doi: 10.1117/12.188021; https://doi.org/10.1117/12.188021

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