APPARATUS FOR MEASURING PATTERN WIDTH OF PRINTED WIRING BOARD

摘要

PURPOSE:To accurately measure a pattern width by calculating the center of a through-hole and the min. radius between said center and the outside of the annular pattern in contact with the outside of said through-hole and subtracting the radius of the through-hole from the min. radius. CONSTITUTION:The image signal of a substrate 13 is inputted to the A/D converter 16 of an image processor 15 as an analogue signal from an image sensor 14 to output a multivalent image 17. This multivalent image 17 is processed at a certain threshold level by a binarization processing part 18 and a binary image 19 wherein an annular pattern is set to a white image and other part is set to a black image is outputted to a pattern width measuring and processing part 20 to measure a pattern width. The center of a through-hole and the min. radius between said center and the outside of the annular pattern in contact with the outside of said through-hole are calculated by the processing part 20 and the radius of the through-hole is subtracted from the min. radius to measure the min. pattern width.