2026-10-02T10:17:12Zhttps://docta.ucm.es/rest/oai/request

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 535 Design Codes Light Óptica (Física) 2209.19 Óptica Física © 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. Centro de Innovación del Transporte (CENIT), España Ministerio de Industria, Turismo y Comercio, España Comunidad Autónoma de Madrid (CAM) Universidad Autónoma de Madrid (UAM) Depto. de Óptica Fac. de Ciencias Físicas TRUE pub 2023-06-20T03:42:35Z 2023-06-20T03:42:35Z 2009-09-01 journal article https://hdl.handle.net/20.500.14352/44293 1084-7529 10.1364/JOSAA.26.001901 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 application/pdf Optical Society of America