What is FPC? Structure and Materials of Flexible Substrates (The Role of Glass Epoxy) Explained

【What is FPC? Explaining the Structure and Materials Used in Flexible Substrates (The Role of Glass Epoxy)】

FPC (Flexible Printed Circuit) is an essential substrate for the miniaturization and weight reduction of electronic devices. The materials supporting its performance include polyimide (PI), which provides flexibility, and glass epoxy (FR-4), which is used as a reinforcing plate, each playing a crucial role.

【Overview】

In recent years, the demand for FPC (Flexible Printed Circuit), which enables high-density wiring in limited spaces due to miniaturization and advanced functionality, has been expanding in smartphones, EVs, in-vehicle devices, medical equipment, and other applications. FPC is known as a "bendable substrate," but to maximize its performance, material selection tailored to the application is essential. Polyimide (PI) film is primarily used as the base material, while glass epoxy (FR-4) is utilized as an important material supporting FPC reliability, for example, by being adopted as reinforcing plates or in the rigid sections of rigid-flex PCBs.

【Features of FPC】

FPC is a highly flexible printed circuit board that uses polyimide (PI) film as its base material and has copper foil circuits formed on its surface. Because it can be freely bent, it enables wiring in narrow spaces, contributing to the miniaturization and weight reduction of electronic devices. Furthermore, its high wiring flexibility and the simplification of component count and wiring can lead to improved assemblability and reliability.

【Role of Glass Epoxy (FR-4) in FPC】

Glass epoxy (FR-4) is not the base material for FPC but is widely used as a reinforcing plate (stiffener) for the sections where electronic components are mounted. By increasing the rigidity of the mounting sections, it helps suppress deformation during SMT assembly, reduces stress on solder joints, and contributes to stabilizing assembly quality. Additionally, in rigid-flex PCBs combining FPC and FR-4, FR-4 is used as the material for the rigid sections, achieving both the flexibility of FPC and the rigidity of the board.

【Applications of FPC】

FPC is widely adopted in products requiring high-density wiring and space-saving designs, including smartphones, tablets, wearable devices, in-vehicle cameras, ADAS, EV-related equipment, medical devices, and industrial equipment. In recent years, further demand expansion is expected with the increasing electronification of automobiles and the proliferation of IoT devices.

【Industries Where FPC is Used】

FPC is used in a wide range of fields requiring high reliability and mounting precision, including the electronics and electrical equipment industry, semiconductor manufacturing equipment, the automotive industry, communication devices, medical devices, and industrial machinery.

【Features of MEISEI INTERNATIONAL TRADING's Glass Epoxy Solutions】

MEISEI INTERNATIONAL TRADING offers optimal resin materials tailored to applications and drawing specifications, including glass epoxy (FR-4) used for FPC reinforcing plates and insulating components. In addition to material sales, we also handle high-precision NC machining, enabling us to provide processed products such as reinforcing plates and insulating components as a one-stop solution. Furthermore, leveraging the collaboration of our bases in Japan, Vietnam, and other locations, along with our supply chain, we flexibly respond to orders from small lots to mass production, supporting our customers in solving their procurement and processing challenges.

If you are interested in procuring glass epoxy from Vietnam, please feel free to contact us. Further details can be found in our catalog.