A flexible printed circuit (FPC) is a special type of printed circuit board that’s characterized by the use of a flexible material. Rather than printing the circuit on a hard substrate, it’s printed on a flexible substrate. This allows for several unique benefits, including a more varied number of applications as well as reliability, durability and overall quality. There are different types of circuits used in FPCs, however, each of which has its own characteristics. If you’re thinking about buying an FPC for your company, you should familiarize yourself with these different circuit types so that you can choose the right FPC for your specific needs.
Circuit Class 1
The lowest grade of FPC, class 1 circuits have undergone only the minimum amount of testing and inspection as per the IPC-6013. You typically won’t find them in touchscreen devices, smartphones or human machine interfaces (HMIs). Rather, they are used for manufacturing disposable electronic devices, such as disposable cameras. Class 1 FPCs are inexpensive, but they don’t bring much to the table in terms of longevity.
Circuit Class 2
A step up from class 1 FPCs is class 2. As you may have guessed, class 2 FPCs have undergone a more stringent testing and inspection process. They typically last long and perform better than their class 1 counterparts. Because of these characteristics, you’ll often find class 2 FPCs in traditional electronics. It’s a cost-effective approach to manufacturing electronic devices that doesn’t sacrifice quality.
Circuit Class 3
Finally, class 3 FPCs are those designed with the upmost attention in regards to testing, inspection and performance. Due to their high cost, though, they are often used for military purposes rather than consumer or commercial applications.
To recap, there are three classes of FPCs. Class 1 is the lowest and is characterized by the use of minimum testing and inspection. Class 2 goes beyond the minimums to create a higher quality FPC, while class 3 FPC is the highest quality. All FPCs are designed on a flexible substrate — something that’s not found with traditional printed circuit boards.
Whether it’s a class 1, class 2 or class 3, FPCs are often equipped with a backlight to illuminate the device and provide the user with greater visibility. Although they support a variety of backlights, light-emitting diode (LED) is the most popular. LED backlights last longer and consume less energy than any other backlighting solution on the market, making them the preferred choice among manufacturers as well as the companies that buy them. Alternatives to LED backlighting include electroluminescent (EL) and fiber optics.