Print Quality Inspection System Based On Humar Response For A Wire Dot-Matrix Printer

This paper discusses a high-contrast imaging capture system and a wire inspection algorithm for an automatic visual inspection system. On IC assembly lines, automated visual inspection is essential to maintain IC productivity and reliability. An automatic inspection system requires realtime inspection without defects overlooked.To overcome the difficulties of getting clear wire images and inspecting flexible object shapes, we developed a high-contrast imaging capture system and a wire inspection algorithm. The imaging capture system consists of a special camera, called a MegaCamera, by Fujitsu Ltd., and structured lighting. The MegaCamera satisfied both the requirements of 10-micron -per -pixel inspection resolution and an image capture area of 20 mm square. The structured lighting optic enabled us to get bright wire images and to reduce background noise. The wire inspection algorithm is based on border following. The algorithm enabled us to inspect curved and straight wires and to detect defects including broken wires, too close wires, and incorrect wiring paths.When we installed the system on an actual IC assembly line, it took 28 s to inspect a 68 -wire IC. The rate of correct detection is 99.7 percent for ICs and the rate of overlooked defects is 0 percent. These results indicate the system can inspect in real time without defects overlooked, which up to now have required visual inspection.

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“…It is therefore difficult to get good wire images. (2) Inspecting wire shapes: The wire path is not completely straight.…”

Section: Introductionmentioning

confidence: 99%

“…We designed a special illumination based on structured lighting techniques. (2) A high -resolution camera:…”

Section: Introductionmentioning

confidence: 99%