WINDING STATE EVALUATION METHOD OF TAPELIKE FILM AND WINDING METHOD OF TAPELIKE FILM

摘要

A winding state evaluation method of a tapelike film includes a step of determining the attenuation rate of ultrasonic wave for the tapelike film (2) by sending an ultrasonic wave to the tapelike film (2) in parallel with the direction of the axis of rotation of a core and receiving its reflected wave or transmitted wave, and a step of evaluating the winding state of the tapelike film (2) from the distribution state of the attenuation rate in the tapelike film (2). The method can judge the winding state of the tapelike film objectively by presenting its numerical representation concretely without relying upon sensual evaluation.