Common Types of Flexible Printed Circuit Construct

A flexible printed circuit (FPC connector), is a type of connector used in electronic devices. Also referred to as flex circuit, flex print, and flexi-circuit, an FPC consists of a thin polymer film with circuit patterns and thin polymer coating that protects the conductor circuits. 

FPCs are generally differentiated depending on their construction. Some of the types are single-sided, double-sided, multilayer, rigid flex, sculptured, and polymer thick film.

 

Considered the most basic type of a flexible printed circuit, a single-sided FPC is characterized by a single layer of conductor made of a metal or conductive polymer on a flexible dielectric film. This is preferably used for high-density edge connection (HDEC) applications.

 

This type of FPC may be manufactured with or without a cover layer, which is a protective barrier that is usually on the top side of the flex. As opposed to a wiring harness, a single-sided FPC features dynamic flexing ability.

 

This type of flexible printed circuit is characterized by two layers of conductors which are then separated by laminated dielectric, usually with plated through holes. This enables the FPC to provide signal sequencing, signal matching, and high-density interconnection.

 

A double-sided FPC connector may be manufactured with protective cover layers on one, both, or neither side of the completed circuit. This allows access to circuit traces from both the top and bottom sides of the circuit, resulting in design flexibility and increased functionality.

 

It also offers the same level of dynamic flexing (from repetitive movements) as a single-sided printed circuit. Because of its ability to minimize interconnect errors, it also offers reduced assembly costs and an overall reliable interconnection.

 

This type of flexible printed circuit as three or more conductor layers that are separated by laminated dielectric, usually with plated through holes. This provides configuration combinations of signal, power, and ground in a high-density interconnection.

 

The number of conductor layers designed into this type is limitless. However, it is important to consider layer count as opposed to flexibility when designing a layout of this type so as to ensure ease of installation.

 

Considered a hybrid construction flexible printed circuit, the rigid flexible printed circuit consists of rigid and flexible substrates that are laminated together to form a single structure.

 

This is the preferred type of FPC used in the commercial avionics and automotive manufacturing industries.

 

One of its distinct features is a rigid board in the component mounting area. Because of this, it is capable of a wide range of flexure in the areas of bend, allowing for ease of installation.

 

The rigid FPC also meets double-sided assembly requirements and allows for the placement of both fine-pitch and small components.

 

This type of flexible printed circuit is a combination of single- or double-sided flexible printed circuit with plated through holes, which provide terminal pins that are sculptured, built in, and extend beyond the polyimide base material.

 

Because of these built-in contacts, there is no need to purchase connectors.

 

A polymer thick film flexible printed circuit features conductors that are actually printed on a polymer base film. This, however, features lower conductivity, rendering it not suitable for all types of applications. It performs well in low-power applications at slightly higher voltages, such as in the case of using a keyboard for a computer.

 

These types of FPC connector offer a variety of solutions to interconnection needs for electronic equipment. With its miniature size, reliable performance, malleability, and high-power functionality, and a flexible printed circuit is today one of the most common and cost-effective interconnection solutions in the market.