Method for visual inspection of multilayer printed circuit boards.

摘要

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 ultraviolet 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.