FPC flexible printed circuit board, also known as "soft board", is a printed circuit made of flexible insulating substrate, which has many advantages that hard printed circuit boards do not have. For example, it can bend, wind and fold freely, can be arranged arbitrarily according to the space layout requirements, and can move and expand freely in three-dimensional space, so as to achieve the integration of component assembly and wire connection. The volume of electronic products can be greatly reduced by using FPC, which is suitable for the development of electronic products in the direction of high density, miniaturization and high reliability. Therefore, FPC has been widely used in aerospace, military, mobile communications, laptops, computer peripherals, PDAs, digital cameras and other fields or products.
FPC also has the advantages of good heat dissipation and solderability, easy assembly and connection, and low comprehensive cost. The design of soft hard combination also makes up for the slight shortage of the flexible substrate in the component bearing capacity to a certain extent.
Flexible printed circuit board can be divided into single-sided, double-sided and multilayer boards. The substrate used is mainly polyimide copper clad laminate. This kind of material has high heat resistance and good dimensional stability. It is pressed with the covering film with both mechanical protection and good electrical insulation properties to form the final product. The surface and inner conductors of double-sided and multilayer printed circuit boards are metallized to realize the electrical connection of the inner and outer circuits. The functions of FPC can be divided into four types, namely, Lead Line, Printed Circuit, Connector and Integration of Function, which cover the scope of computers, computer peripheral auxiliary systems, consumer appliances and automobiles.