DETECTION OF FOLD OF PRINTED CIRCUIT BOARD

摘要

PURPOSE:To detect the folded part of a printed circuit board by irradiating excitation light of a short wavelength on the surface of the printed circuit board to obtain the image of the fluorescence generated from the folded part of the substrate and detecting the signal of a specified level of above in the photoelectric conversion signal of said image. CONSTITUTION:The excitation light 8 having the limited wavelength region board by passing the light from a high-luminance light source 4 through a filter 7 is sent to a half mirror 9, by which the optical path is changed and the light is irradiated on the printed circuit board 1. The fluorescence is generated if the substrate 1 has the folded part. Synthesized light 10 of the reflected ligth and fluorescence from the substrate 1 is made incident to a filter 11 so that only the fluorescence 13 is transmit ted through the filter. The formed image is photoelectrically converted in a detecting part 14. A video siganl 15 is inputted to a binary coding circuit 16 which detects the presence or absence of the folded part from the prescribed threshold value. The excitation light is irradiated on the substrate surface and the fluoresence is generated by the folded part in the above-mentioned manner and therefore the fold of the sub strate which may lead to the disconnection of wiring patterns is automatically detected with good accuracy.