applications of flexible circuits
There are millions of devices that partially or fully depend on flexible circuits. While different applications require varying degrees of fabrication care and design consideration, many share some common attributes that can help designers determine the best options for their project. These include the ability to fold, roll or bend a circuit board to accommodate its physical environment, high-density device populations that use point-to-point connections and shortened thermal paths.
In addition, a primary advantage of flexible circuits PCBs is their relative mechanical flexibility, which can be especially beneficial in products that need to endure dynamic environmental stresses such as folding or repeated bending. This is why it’s important to work with a PCB fabricator that specializes in flex technology and understands the specific materials, processes and challenges involved.
A flex circuit’s copper conductors are typically formed on a substrate, such as polyimide, often known by the brand name Kapton, which has been used for multiple space missions to deliver electrical signals throughout a spacecraft. The material is photolithographically patterned to create the desired layout of copper traces. Unwanted areas are chemically etched away to leave only the desired circuits, which are then plated with metals. A protective coverlay coating is applied to the substrate and traces, openings for solder pads are created and components are mounted using either surface mount or conductive adhesive mounting methods. The resulting flexible printed circuit board is then subjected to rigorous electrical and mechanical testing.
What are the primary applications of flexible circuits?
Flex circuits can be produced as a single-sided or double-sided board. Single-sided flex circuits are an attractive option for simple designs and have the added benefit of cost effectiveness, which makes it possible to incorporate a flex circuit into a limited budget. Multi-layer flex circuits are able to handle more complex and demanding circuitry, and they can also be designed to include shielding or additional support mechanisms that are impossible or impractical to add with single-sided flex boards.
In the past, flexible electronic circuits were often built on a flat piece of plastic or other material that was folded and twisted to form its shape. Early patents described coating paper with paraffin or laying flat metal conductors on top of it to create flexible electric circuits. The invention of automated production processes in the 1940s made it feasible to replace the traditional wiring harness with a flexible circuit. A flexible circuit board eliminates the need for mechanical connectors, allowing it to route directly to the points specified by the design plan and significantly reduces overall assembly time.
Some of the most popular flexible circuits are found in mobile devices like phones, tablets and laptop computers. As these products become more compact, their internal hardware needs to fit in smaller spaces and withstand the stress of constant handling. This is why they are perfect candidates for a flex circuit. In addition, cars are becoming increasingly equipped with advanced electronics such as e-paper and LCD displays that rely on a flexible circuit to operate.
