Method for visual inspection of multilayer printed circuit boards
US4697923A · kind A · utility
17Cited by
9References
5Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Mar 25, 1986 |
| Grant date | Oct 6, 1987 |
| Priority date | — |
| Expiry date | Mar 25, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K2203/161
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method is disclosed for the visual inspection of electrical circuitry deposited in the layers of a multilayer printed circuit board wherein the dielectric layers of the multilayer board are prepared using a clear, light transparent thermosetting resin having incorporated therein a dye which is permeable to visible light but which absorbs light in the 320-440 nm region. The electrical circuitry in the board can be easily traced by an observer upon illumination of the board by visible light.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.