Web longitudinal position sensor

摘要

Methods and systems for determining longitudinal position of an elongated web are described. Sensors are used to detect one or more substantially continuous fiducial marks disposed longitudinally on the web. The sensors generate signals associated with the fiducial marks. A position detector receives the signals and determines a longitudinal position of the web using the sensor signals. The fiducial marks may be periodic fiducial marks, such as sine and/or cosine marks on the web and/or may be piecewise continuous marks. The coarse longitudinal position of the web can be determined based on periodically recurring features of the fiducial marks. The fine longitudinal position can be determined based on continuous portions of the fiducial marks between the periodically recurring features.

主权项

1. A method to determine the position of an elongated web, comprising:
sensing one or more continuous fiducial marks disposed longitudinally on at least a portion of the web, wherein sensing the one or more continuous fiducial marks comprises sensing a sine fiducial mark and a cosine fiducial mark disposed longitudinally and deposited on the web; and determining a longitudinal position of the web based on the fiducial marks.