Highly accurate measurement of sheet thickness: the planar error correction

In the present study, the authors describe a system using optical and magnetic sensors to measure the thickness of polymer sheets accurately. A newly developed planar error correction method used in the manufacturing process of the sheet is also presented. The system was drastically improved for the precision of measurement of the polymer sheet, resulting in a precision of /spl plusmn/1% or less. As a result, we have succeeded to produce sheets with thickness of 300 /spl mu/m at a manufacturing process speed of approximately 30 m/min.