Flexible Printed Circuits Contribute to Miniaturization
With the continuous push for electronic miniaturization across numerous industries, manufacturers are requiring smaller and thinner devices that can be assembled quickly and efficiently. These devices include everything from cell phones and tablet computers to implantable medical equipment, automotive components and aerospace equipment. All of these devices require extremely thin base materials that are able to take on electrical functions without sacrificing stability or performance. Fortunately, advances in printed circuit board technology have made it possible to create thin, flexible devices without sacrificing the integrity of the core function. This advancement has been driven by the introduction of printed flexible circuits (FPCs).
Flex circuits are a great solution to many electronics packages that have traditional wiring methods such as soldered wires, hand-wired connectors and bare metal terminations. With the ability to be bent, shaped and manipulated in a way that can be integrated into the final product with ease, flex circuits provide engineers with tremendous design options for their products.
A flex circuit is similar to a PCB in the fact that it contains various layers of copper, conductive paths and supporting material, however the difference is that the board can bend and flex. A flex circuit also has the ability to withstand dynamic bending that can occur during installation or in use. This flexibility provides for a variety of packaging solutions that cannot be accomplished with a standard rigid PCB and can significantly reduce the overall weight of the final device.
How Flexible Printed Circuits Contribute to Miniaturization
The main element that enables the flexibility of a flex circuit is the choice of material from which the conductor patterns are formed. Unlike PCBs, which are usually constructed from laminates that contain copper and dielectric layers that must be etched to create the pattern of conductor lines, flex circuits typically use a thin layer of copper foil that is bonded to a thicker dielectric layer of polyimide or a similar polymer. The thickness of the metal can vary depending on the application, but a wide range of metallic and dielectric choices are available.
Adding to the flexibility of a flex circuit is that the holes needed for insertion and soldering are not pre-formed in the material, but rather created after the etching process using drilling mechanisms. This allows the designer to have control over the size of these metal pads, allowing them to be placed where they are needed and providing the best possible performance for a device.
Another key component to the flexibility of a flex circuit comes from the fact that the entire board is built as one unit. This helps to eliminate the potential for errors when assembling, handling and repairing the finished product. This can significantly cut down on labor and assembly costs compared to standard hard board constructions.
Lastly, the flexibility of a flex circuit allows for extremely narrow lines and spaces giving room for higher density applications. The higher densities that are possible with a flex circuit help to free up space for additional features in the finished product, a significant advantage over standard PCBs. This is especially true for high-performance applications that are expected to perform under harsh conditions, such as the automotive industry, where devices are constantly subjected to vibrations and mechanical stress.
