MANUFACTURE OF THROUGH HOLE SUBSTRATE AND INSPECTION METHOD FOR THROUGH HOLE

摘要

PROBLEM TO BE SOLVED: To enable inspection of even fine through holes by making light of a spot light source parallel to project onto a through hole substrate and detecting the leaked light from the through holes. SOLUTION: Through holes are irradiated with light of a sot light source 13 through a lens 14 from below a printed circuit board 1 being conveyed by a belt conveyor 10. The light passing through the through holes is caught by a line sensor camera 11 to aggregate the number of the through holes with a number of hole converting device 12. In this process, the light of the spot light source 13 is made substantially parallel by the lens 14 and when a relationship of D/H tanθ(wherein D represents the diameter of through holes and H the thickness of printed substrate 1) is met, the light can pass through the through holes so that the leaked light is focused onto the line sensor camera 1. This enables inspection of piercing through microscopic holes and also allows automation thereby shortening inspection time.