Flexible circuits provide four major benefits over rigid PC boards.
Design Freedom The most immediate benefit that flexible circuits(Flex PCB) give a package designer is an almost unlimited degree of design freedom. Flex circuits can fit in tight spaces. They can bend, fold, twist, change in width many times and even flex from a rolled configuration. This gives the package designer the freedom to relocate other parts and subassemblies where they will optimize circuit and equipment operation. The designer is no longer restricted by the space demands of bulky, rigid PC boards.