MEASURING INSTRUMENT OF SHRINKAGE DEGREE OF FILM

摘要

PURPOSE:To reduce the number of processing operations for marking scales by indicating the shrinkage degree of a film to be measured by a scale at a position of a gap of stripe patterns where the quantity of light passing through the overlapped position of patterns is first out of sight after being gradually reduced from the side of a measuring reference pattern. CONSTITUTION:The position where the light does not leak when a positioning reference pattern 3 overlapped with a reference pattern 6 to be measured is placed on a see- through bed 8 is made a reference point for measuring the shrinking ratio of stripe patterns formed both on a measuring instrument 4 and on a film 5 to be measured. The film 5 is such one that is used in forming patterns onto a printed circuit board or the like. Based on the position of a gap of scale stripe patterns 2 formed on a transparent flat plate 1 which gap is corresponding to a gap (g) where the stripe pattern 2 is overlapped with a stripe pattern 7 to be measured formed on the film 5 having the larger shrinking ratio than the flat plate 1 where the quantity of light passing through the gap (g) is first out of sight after being gradually reduced from the side of the positioning pattern 3, the shrinking ratio can be calculated with the use of the distance between the position of the gap and the reference point and the value of the gap (g) in a simple manner.