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Location of Covered Vias in Circuit Boards Disclosure Number: IPCOM000041080D
Original Publication Date: 1987-Jul-01
Included in the Prior Art Database: 2005-Feb-02

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Interrante, M Williams, D Ziemins, A [+details]


Polarized light is used to illuminate E.C. pads 10 with via holes 12 beneath them. A camera is polarized for maximum contrast detection. When this image is converted to black and white, the edges of the pad and the via "glow", whereas the rest of the pad is dark. (Image Omitted)