Flexible printed circuit boards (flex PCBs) use thin, bendable substrates—typically polyimide or similar polymers—instead of rigid fibreglass, allowing circuits to flex, fold, or conform to curved surfaces. Conductors are etched or deposited on the flexible base; multilayer and rigid-flex variants combine flexible and rigid sections for dense interconnection. Flex PCBs reduce weight and volume, improve reliability under vibration and thermal cycling, and enable form factors that rigid boards cannot. They are widely used in consumer electronics (displays, hinges), wearables, medical implants, and aerospace—including spacecraft and satellites, where mass and reliability are critical.
The technology addresses the need for electronics in constrained or dynamic mechanical environments. In space systems, flex and rigid-flex boards support avionics, payloads, and solar array deployment with lower mass and better resilience to launch and thermal loads. Multi-level integration in compact packages is possible by folding or stacking flex layers. Materials and processes continue to improve for higher density, better thermal management, and harsher environments.
Challenges include cost (especially for complex rigid-flex), design for flex and fatigue, and repair or rework. As missions and devices demand more functionality in smaller, lighter packages, flexible printed circuit boards will remain a key enabler for aerospace, medical, and consumer applications.