Method of and device for determining positioning between a hole and a wiring pattern on a printed circuit board by utilizing a set of area values
US5347591A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 29, 1991 |
| Grant date | Sep 13, 1994 |
| Priority date | — |
| Expiry date | Oct 29, 2011 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S706/912
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A printed board, on which a wiring pattern and a through hole to be inspected are provided, is scanned pixel by pixel and is read optically. The data obtained by scanning is converted into an electric signal to obtain image data. On the basis of the image data thus obtained, a pattern image representing the wiring pattern an a hole image representing the through hole are obtained. A center and a radius of the hole image are obtained from the image data. Then, a plurality of ring-shaped masks are obtained by magnifying the hole image at a plurality of magnifications. The size of the pattern image is normalized by the size of the hole image, and the, respective areas of overlapped regions between a plurality of the ringshaped masks and the pattern image are detected. Since these areas are obtained with an isotropic method, they do not depend on the directions of a line entering a land. By simulation, correspondence between the area of the overlapped regions and a relative positional relation between the wiring pattern and the through hole is obtained in advance. On the basis of this known correspondence, a relative positional relation between the wiring pattern and the through hole i…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.