Capacitive switch circuitry on flexible printed circuit layer

Not all electronic devices feature a rigid circuit. In recent decades, flexible printed circuits (FPCs) have become more common. They still consist of conductive pathways that provide the electrical connections for a device, but FPCs are characterized by the use of a flexible substrate, which isn’t found in their rigid counterparts. While all FPCs are created on a flexible substrate, though, they are available in different types.

#1) Single-Sided

Single-sided FPCs are exactly what they sound like: They consist of a single-sided flexible substrate. Only one side of the flexible substrate features conductive pathways. This side typically features some form of conductive metal, which is used to create the conductive pathways. The other side remains empty and devoid of any conductive pathways. Single-sided is one of the most common types of FPCs.

#2) Double-Sided

Also known as double access FPCs, double-sided FPCs feature conductive pathways on both sides. They are essentially the opposite of single-sided FPCs. Single-sided FPCs only have conductive pathways on one side, whereas double-sided FPCs have conductive pathways on both sides. They still feature a flexible substrate. With double-sided FPCs, the conductive pathways are created on both sides of this flexible substrate.

#3) Multilayer

There are also multilayer FPCs. Multilayer FPCs are characterized by the use of multiple layers. By definition, multilayer FPCs must have at least three separate layers. Other FPCs typically have one or two layers. Multilayer FPCs go one step further by requiring the use of at least three separate layers.

#4) Rigid-Flex

When researching some of the different types of FPCs, you may encounter rigid-flex. Rigid-flex is a unique type of FPC. Unlike other FPCs, it’s not a true FPC. Rather, rigid-flex is a hybrid circuit type that combines elements of both FPCs and rigid circuits. This is why it’s known as “rigid-flex.”

Most rigid-flex FPCs feature multiple layers. Some of these layers are rigid, whereas others are flexible. Both types of layers are joined together to create a rigid-flex FPC. In this regard, rigid-flex FPCs are technically hybrid circuits.

#5) Sculpted

Finally, there are sculpted FPCs. What are sculpted FPCs exactly? Sculpted is a category of circuits that are defined by their production method. They are produced using etching. Etching is a production process that involves the creation of conductive pathways . The conductive pathways are etched onto the substrate. Sculpted FPCs are producing using this sculpting or etching process.