Method of and apparatus for inspecting conductive pattern on printed board
US5144681A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 22, 1991 |
| Grant date | Sep 1, 1992 |
| Priority date | — |
| Expiry date | Mar 22, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2207/30141
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A printed circuit board (11) is provided with a conductive pattern (P, R) and a through hole (H) thereon. Respective images of the conductive pattern and a through hole are photoelectrically read with an image reader (20). The conductive pattern image is magnified in size to obtain a magnified pattern image (PI.sub.m), while the hole image is magnified at different magnification factors to obtain magnified hole images (HI.sub.n, HI.sub.n-i). A ring image (RP) is defined by the difference of the magnified hole images. The overlapped region (WR) on which the ring image and the magnified pattern image overlap each other is then calculated, and a defect or an opening of the conductive pattern is detected by calculating the aperture angle (.theta.) of the overlapped image.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.