Method and apparatus for inspection of solder joints utilizing shape determination from shading
US5064291A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 3, 1990 |
| Grant date | Nov 12, 1991 |
| Priority date | — |
| Expiry date | Apr 3, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2201/102
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Inspection of solder joints utilizing ilumination, reflected light intensity measurements to determine surface heights and comparison with predetermined inspection criteria to determine the integrity of the solder joint. A solder fillet (16b) is sequentially illuminated from first and second angles and optically scanned and reflected light intensity values at incremental values of inclination are measured. The heights of the fillet wall (16d) at predetermined points and the integrity of the fillet (16b) are determined using the measured reflected light intensity values and either using real-time computation or accessing an array of predetermined incremental inclination values as a function of the reflected light intensity values. Alternatively, the ratio of the sensed reflected light intensity values at each point may be used as an input variable to a one dimensional look-up table or for real-time computation. The solder fillet may be coated with a matte coating.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.