Improved electroluminescent and photonic devices with integrated logic and control circuits are disclosed. The feed lines are directly connected, at their inner ends 27, 28, to the connecting surfaces 22, 23, the switch 10 being encased by an insulating protective layer 32, and the feed lines, at their free ends 29, 31 which are remote from the inner ends 27, 28, are free of the protective layer 32. The distal end is used as a pick to test the integrity of the formed seam and the curved section is used for applying pressure to specific areas on the seam.