What are the different types of flexible circuits configurations available?

types of flexible circuits configurations available

Designed for use in a variety of applications, flexible circuits are used to solve problems that cannot be resolved using traditional wiring methods or rigid printed circuit boards (PCBs). The flexibility and foldability of flex circuits makes them ideal for assembly processes that require greater mobility and the ability to withstand demanding environments. They are also used in many different products such as calculators, cell phones, printers, LCD televisions and cameras, as well as medical equipment like heart monitors and pace makers, manufacturing equipment such as robotic arms and processing machines, and aerospace/military applications.

In most cases, a flexible circuits is composed of multiple copper conductive layers that are separated by insulating layers. These layers are usually etched from metal foil, with the exception of a few special cases. A wide range of metals are used to create the conductive patterns, but copper is the most common because of its balance of cost and physical and electrical performance.

The polymer substrate, or dielectric layer, that forms the base for a flexible circuit is often a flexible material such as polyimide. This polymer film provides the primary physical and electrical properties of a flexible circuit, although it can be combined with other materials for specific application requirements. A conductive pattern is printed on the surface of the polymer with either photo imaging or laser imaging, and holes are then created through this layer to connect to other components in the device.

What are the different types of flexible circuits configurations available?

Single-sided flex circuits have a conductor layer on one side of a flexible dielectric film, and these features are accessible from only that one side. These are the most common variant for dynamic flexing applications, and they can be coated with a protective layer if desired. Dual access flex circuits, which are also sometimes called back-bared flex circuits, have a conductor layer on both sides of the flexible dielectric film and allow access to selected features from both sides. They are plated with metalized through holes to make connections.

Another variant is a multi-layer flex circuit, which consists of multiple copper layers separated by dielectric layers that are connected through plated through holes. The multi-layer structure enables more complex interconnections and allows for a higher component density than single-sided or double-sided circuits.

Rigid-flex circuits, which are designed for static flexing applications, have the same basic construction as a multi-layer flex circuit but combine rigid and flexible elements. They are often a good choice when high reliability is required in a static environment, and they can be coated with a plastic to protect against scratches and dents.

The etching process is what gives a flexible circuit its unique characteristics, and there are several different types of etching processes that can be used to produce the desired conductor patterns. Most commonly, photolithography is used to make a circuit pattern on the copper layer, and these circuit patterns are then transferred to the appropriate location with laser imaging or photo masking. The final result is a high-quality, reliable and durable circuit that is flexible, thin, lightweight and easy to mount.