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Proceedings Paper

Automated Optical Pattern Inspection For High-Density Printed Wiring Boards
Author(s): Moritoshi Ando; Hiroshi Oka; Satoshi Iwata; Takefumi Inagaki
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Paper Abstract

A new technique for automated optical inspection of printed wiring boards (PWBs) has been developed. It uses black line sensing and a radial matching algorithm. The sensing method uses black line illumination and a CCD line sensor. The PWB is brightly illuminated except for the area under observation. Because the PWB substrate is translucent, copper patterns are sensed as shadows and their color and roughness do not affect the sensing. The inspection algorithm describes the copper pattern with binary codes. The pattern width is measured radially in four directions from the pattern centers. A combination of length and direction is encoded in a 12-bit binary code. Codes are assembled and make up a dictionary. The method can be used to inspect many kinds of patterns by changing the contents of the dictionary. An inspection system using this technique has a 5-μm resolution and can inspect a 490 x 540 mm area in 5 minutes.

Paper Details

Date Published: 21 March 1989
PDF: 7 pages
Proc. SPIE 1004, Automated Inspection and High-Speed Vision Architectures II, (21 March 1989); doi: 10.1117/12.948982
Show Author Affiliations
Moritoshi Ando, Fujitsu Laboratories LTD. (Japan)
Hiroshi Oka, Fujitsu Laboratories LTD. (Japan)
Satoshi Iwata, Fujitsu Laboratories LTD. (Japan)
Takefumi Inagaki, Fujitsu Laboratories LTD. (Japan)

Published in SPIE Proceedings Vol. 1004:
Automated Inspection and High-Speed Vision Architectures II
Michael J. W. Chen, Editor(s)

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