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oai:docta.ucm.es:20.500.14352/442932023-08-27T18:30:20Zcom_20.500.14352_14col_20.500.14352_15

Correlation technique for the compensation of diffraction widening of optical reference signals Saez Landete, José Alonso Fernández, José Sánchez Brea, Luis Miguel Morlanes Calvo, Tomás Bernabeu Martínez, Eusebio © 2009 Optical Society of America. This work has been supported by Center for Innovation in Transport (CENIT) project “Tecnologías avanzadas para los equipos y procesos de fabricación de 2015: e-eficiente, e-cológica, e-máquina (eEe)” of the Ministerio de Industria, Turismo y Comercio of Spain and by the Madrid Autonomous Community-University of Alcalá de Henares (CAM-UAH) project CCG08-UAH/TIC-3941. Two-grating measurement systems are routinely employed for high-resolution measurements of angular and linear displacement. Usually, these systems incorporate zero reference codes (ZRCs) to obtain a zero reference signal (ZRS), which is used as a stage-homing signal. This signal provides absolute information of the position to the otherwise relative information provided by the two-grating incremental subsystems. A zero reference signal is commonly obtained illuminating the superposition of two identical pseudorandom codes and registering the transmitted light by means of a photodiode. To increase the resolution of the system, a reduction of the grating period and the ZRC widths is required. Due to this reduction, the diffractive effects produce a widening of the ZRS and, in turn, a loss of the measuring accuracy. In this work, we propose a method to narrow the distorted signal obtained with a Lau-based encoder, reinstating the accuracy of the ZRS. The method consists of the inclusion of a correlation mask on the detector. A theoretical model to design the mask has been developed, and experimental results have been obtained that validate the proposed technique. 2023-06-20T03:42:35Z 2023-06-20T03:42:35Z 2009-09-01 journal article 1084-7529 10.1364/JOSAA.26.001901 https://hdl.handle.net/20.500.14352/44293 http://dx.doi.org/10.1364/JOSAA.26.001901 http://www.opticsinfobase.org eng Tecnologías avanzadas para los equipos y procesos de fabricación de 2015: e-eficiente, e-cológica, e-máquina (eEe) CCG08-UAH/TIC-3941 open access Optical Society of America