Shrinkage-absorbing potted PCB holding electronic components - has cushioning layer of e.g. polyurethane foam bonded to e.g. polycarbonate film embedded between PCB and outer casing to absorb stresses

摘要

Electronic circuit which is potted in a casing, and a proximity switch in particular, has a PCB with electronic components, all embedded in a cast material. An elastic cushioning material is also between the casing and PCB and embedded.$ The cushion is pref. a polycarbonate film and polyurethane foam, or a polyurethane or epoxy resin foam.$ ADVANTAGE - Reduces shrinkage stresses on the PCB to acceptable levels.