Image pickup apparatus for a printed wiring board
US4682040A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 6, 1985 |
| Grant date | Jul 21, 1987 |
| Priority date | — |
| Expiry date | May 6, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R31/309
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Disclosed herein is an image pickup apparatus for a printed wiring board comprising a solid state image sensor whose light receiving surface is set to be opposed to the surface of the printed wiring board, a main illumination source arranged to satisfy the law of regular reflection on the surface of the printed wiring board with respect to the light receiving surface of the solid state image sensor and a subsidiary illumination source arranged not to satisfy the law of regular reflection with respect to the light receiving surface of the solid state image sensor thereby to supply the light receiving surface with scattering light by strias formed on copper patterns. The amount of regularly reflected light, which is changed depending on the strias formed on the copper patterns, is substantially compensated by the scattering light, so that the amounts of light received by the solid state image sensor relating to the copper patterns are made substantially constant regardless of the radiation pattern of the strias. In addition, the main and subsidiary illumination sources are formed by light emitting diodes thereby to attain technical and economical advantages.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.