Rigid-flex is a construction in which flexible polyimide layers run continuously through one or more rigid multilayer sections, so linked boards fold into a housing without connectors or cables. The flexible parts usually use rolled annealed copper under coverlay instead of soldermask, and their minimum bend radius is set as a multiple of their thickness. It costs more than separate boards and cables but saves space, weight and connector failures in cameras, medical devices and military electronics.
Going rigid-flex kills two connectors and the ribbon, but the fab wants a 10 to 1 bend radius on the flex tail.
Also heard as
- rigid flex
- flex-rigid
Related terms
Laminate
Sheet of reinforced resin, usually clad with copper foil, that rigid printed circuit boards are built from.
Stackup
Ordered arrangement of copper layers, cores and prepregs that makes up a multilayer board, with each thickness.
Kapton
Amber polyimide tape, named for a well-known brand, used to mask and protect board areas from heat.