Lex IP Meister, PLLC
Apparatus and method of measuring web feeding velocity by using single field encoder
A method of measuring feeding velocity of a web, on which a scale having pitches different from pitches of a mask are formed, is provided. The method includes: calculating a number of vibrations of a moiré image of light passing through the mask and the scale; calculating pitches of the scale of the fed web based on the calculated number of vibrations of the moiré image; averaging the pitches of the scale so that a change in a pitch between adjacent timings among the calculated pitches of the scale is minimized; extracting first signals corresponding to our phases for one pitch based on the averaged pitches of the scale; calculating two second signals for forming a Lissajous circle from the first signals; and calculating an angle of the Lissajous circle by the two second signals and then calculating the feeding velocity of the web by using the calculated angle.
KOREA INSTITUTE OF MACHINERY & MATERIALS
G
G01P
inventional
Jeongdai Dongwoo Seung-Hyun Young Man Kwang-Young Deokkyun Taik Min
Jo Kang Lee Choi Kim Yoon Lee