| 摘要 |
PURPOSE: To recognize a structure defect in a micro range by detecting a solid surface coordinate for calculating a section area of a conductor path with a local evaluation window. CONSTITUTION: A printed circuit board 1 comprises an evaluation window 20 which is lager than the width of a conductor path 2, and the board 1 is scanned by using a laser beam 14, and reflected multiple observation beams are, through objective lenses 3 and 4, introduced in a detecting surface 5 of a high resolution position sensing photo-detector 8. Then, an evaluation device 9 connected to the detector 8 through a optical conductor 7 reads the signals from the detecting surface 5 in parallel, then, by summing up a differential surface area 22, calculates section areas 18 and 19. The detecting surface 5 comprises an array of optical conductors 7.1-7.n, and the detector 8 has differentially possible height step of 50-100. Thus, by comparing the calculated value of section area and gap with a pre-provided threshold, a structure defect of the conductor path can be detected. |
