Flexible printed circuits (FPCs) have become a popular alternative to traditional printed circuit boards (PCBs). While they both consists of intricate conductive paths, FPCs are defined by their flexibility. They can bend and flex without breaking — something that’s not possible with traditional PCBs. If you’re going to buy one or more FPCs, though, there are a few things you’ll need to consider.
You should consider the circuit class when choosing an FPC. There are three primary circuit classes in which FPCs are made. Each class has its own design standards that manufacturers must follow when creating them.
Class 1 FPCs have the lowest level of testing and performance requirements, so they are typically used in disposable electronics. Class 2 FPCs are a step up. They have a medium level of testing and performance requirements, making them ideal for a variety of electronics. Class 3 FPCs, on the other have, have the highest level of testing and performance requirements. Because of their stringent requirements, class 3 FPCs are typically used in military-related electronics.
In addition to the circuit class, you should consider the type variation when choosing an FPC. There are four type variations for FPCs. The type variation refers to the IPC standard.
IPC type 1 consists of a single layer with insulation on both sides. IPC type 2 consists of two layers that are separated by insulation. IPC type 3 consists of at least three layers with insulation between each respective layer. IPC type 4 consists of two or more layers with the ability to support a rigid PCB.
Don’t forget to consider the material when choosing an FPC. Most FPCs are made of multiple layers , each of which consists of a metallic material. Copper is commonly used in FPCs because of its conductive properties. In some FPCs, the copper layers are covered in a thin layer of gold.
Something else to consider when choosing an FPC is backlighting. While not required, FPCs can be constructed with backlighting. Backlighting is a component that’s designed to produce illumination.
FPCs support several types of backlighting. Light-emitting diode (LED) is commonly used in FPCs. LED backlighting is energy efficient, long-lasting and produces a high level of illumination. LED backlighting can also be used with light guides to achieve a more even distribution of illumination. Other backlighting options for FPCs include fiber optic and electroluminescent (EL).