Most people who know circuit boards wonder about flexible PCB applications. With improvements in electrical systems, we’re looking at an area full of potential.
The flexing, bending, and twisting nature of Flex PCBs makes it possible to have unique and compact product designs that can withstand shock and vibrations.
These benefits make flexible boards applicable in multiple use cases, such as in the ever-miniaturizing consumer electronics.
Let’s analyze these applications in detail to understand how these boards are useful in the industry.
Table of Contents
- What are the Main Types of Flexible Circuit Boards
- What are the Application Areas of Flexible PCB
- What are the Future and Developments of Flexible PCB Applications
- What to Consider When Selecting a Flexible PCB For a Certain Application
- What are the Advantages of Using Flexible PCBs in Various Applications
- Flexible PCB Applications FAQs
- Conclusion
What are the Main Types of Flexible Circuit Boards
(Flexible circuit board ribbon cable)
A common thing among flexible circuit boards is that you can fold them without breaking components or electrical traces.
However, some differences distinguish them into several groups. Here, let us look at the types of flexible circuit boards.
Single-Sided Flexible PCBs
The most popular and straightforward flexible printed circuit boards on the market. They have components and traces on one side while the other remains empty. Additionally, they have a single conductor layer atop a stretchable dielectric layer.
Moreover, single-sided circuit boards are the cheapest flex PCBs on the market as they are easier to manufacture.
If you need a simple, flexible PCB for your project, a single-sided flex should be your first choice. They are lightweight and durable, making them common circuit boards in small devices like calculators.
Double-Sided Flex PCBs
From the name, double-sided PCBs have prints on both sides of a dielectric layer. The two sides then connect through plated holes.
As a result, the boards have better circuit density and power-handling capabilities than single-sided flex boards. However, they are costlier to manufacture and assemble.
Multi-Layer Flex Circuit Boards
They are flexible circuit boards made according to IPC Type 3 standards of PCB manufacturing. Moreover, they have three or more flexible layers of conductors that manufacturers separate with insulating films.
On the outside, PCB manufacturers cover the layers with an insulating polyimide layer.
They also employ plated through holes to connect the electrical circuits on each layer. Furthermore, they are ideal for bend-to-fit devices only.
Moreover, they employ high-speed regulated impedance in a surface stripline or microstrip format.
Rigid-Flex Circuit Boards
Rigid-flex PCBs are flexible circuit boards made according to IPC Type 4 standards of PCB manufacturing.
They consist of two or more layers of conductive copper separated by flexible or rigid insulation materials.
They have plated through holes connecting the conducting layers in a multi-layer configuration.
Furthermore, manufacturers selectively add cover film layers to the board’s flexible areas. Consequently, they are ideal for bend-to-fit applications in military devices, among others.
What are the Application Areas of Flexible PCB
In Computer Electronics
One area where we use flexible PCBs is computer electronics. The category contributes the most sales of flexible PCBs in the current market.
Every device you can think of, be it printers or scanners, has a flexible PCB.
With current technology trends calling for smaller devices, it’s only a matter of time before we witness a massive uptake of flex PCBs.
Moreover, they are durable and lightweight, making them ideal for portable devices like cameras and calculators.
In Automotive Industry
Weight is an important consideration when designing automotive electrical systems.
Engineers try to make some vehicles as light as possible by reducing the weight of PCBs and wire harnesses. And the best way to do so is to use flexible PCBs instead of the older rigid circuit boards.
Moreover, as vehicles advance and begin to have multiple sensors and electronics, there’s a need for reliable connections. Engineers would have to connect thousands of wires throughout the car without flexible PCBs.
Luckily, the flex PCBs allow for better thermal and vibration performance within the vehicle.
Flexible PCB Applications In Medical Devices
Flexible PCBs have great use in medical devices due to their flexibility and reliability. Wearable devices are developing into a significant aspect of modern-day medical technology.
Moreover, the ability of flexible printed circuit boards to mimic human forms increases the devices’ durability.
Flexible printed circuits can withstand wear and tear in applications, including hearing aids, crucial sensors, and more. Consequently, they improve the performance and efficiency of these systems.
Other applications of flexible PCBs in medical devices include:
- Implantable devices like defibrillators and neurostimulators
- Wearable devices like ECG and blood pressure monitors
- Diagnostic equipment like CT scanners and MRI machines
- Surgical instruments like endoscopes and laparoscopes
- Drug delivery devices like insulin pumps and infusion pumps
In Smartphones
Flexible PCBs have many smartphone applications due to their performance and low weight. First, smartphone manufacturers use them in smartphone displays, including AMOLED screens.
The flex boards give the engineers design freedom to curve the screens to suit customer preference. Second, we use flex PCBs in camera modules for compact design.
The design flexibility makes connecting the camera sensor to the phone’s main board easier.
Additionally, other applications include use as antennae trace, flexible battery cells, and touch screen sensors. Aerospace and Defense Applications
Mission-critical aerospace and defense applications require reliable electronics, and flexible PCBs provide this benefit in three ways.
First is the flexibility of the circuits, which ensures military equipment and in-flight systems remain functional even when exposed to extreme vibrations.
This flexible nature also allows seamless electronics integration into the curved fuselages and wearable military gear.
The second is the ability to withstand harsh environments. Flexible boards can be built to withstand high temperatures from jet engines, high g-forces, extreme cold, and electromagnetic pulses.
They do all that while having compact and lightweight packages, which is the third reason for using them.
Compact and lightweight electronics are critical, especially for aerospace and aviation applications, because weight and space consumption should be kept as low as possible.
Applications of Flex PCBs in Emerging Technologies
- Internet of Things (IoT): IoT is penetrating all aspects of our daily lives, and flex PCBs are enabling this tech by allowing IoT devices to adopt curved and bendable shapes to create more intuitive human-product interactions.
- Flexible Displays and E-paper Displays: The bendable nature of these boards enables manufacturers to make curved displays that can be rolled or folded into mobile devices.
- Energy Applications: Solar has become one of the most vital renewable energy sources globally, and panels can utilize flexible PCBs to conform to curved installation surfaces or movable mounting systems to maximize sunlight exposure.
- Robotics: The flexibility and compact routing of flex circuits make it possible to create complex robot parts, such as limbs and humanoid structures in general, that can mimic real human movement.
- Wearable Technology (like second skin): Regular and IoT wearables, such as smart jewelry and fitness trackers, rely on the lightweight and low-profile characteristics of flexible boards to perform their intended functions discreetly when worn. This has also made it easier to incorporate electronics into clothing because they can have stretchable interconnects.
What are the Future and Developments of Flexible PCB Applications
Integration with 5G and IoT
The increased rollout of 5G and IoT technologies has driven the growth of the flexible PCB market, and this is expected to continue as more people, businesses, and organizations adopt connected systems and devices, high data transfer rates, and seamless connectivity.
Increased Hybridization With Rigid PCBs
Flexible PCBs might not be the best for all applications because they have some drawbacks, such as limited component mounting and conductive layers.
Combining them with rigid boards, however, introduces the best of both worlds, and this hybridization is expected to continue, especially in some of the applications listed above.
HDI Flexible PCBs
HDI circuit boards have a higher wiring density per unit area than regular boards, which increases electrical performance and reduces the package size.
Such boards will be more common in the defense, medical, and aerospace industries to introduce more functionality in tiny packages.
Embedded Component Flex PCBs
The global trend in electronics involves packing more performance in small spaces.
This requires multiple components mounted on the board, which is limited when dealing with flexible boards.
However, embedding these parts into the board can drive both miniaturization and high component densities, which is a win-win.
This process involves burying active and passive devices inside the board cavities, which reduces the number of external pads, lead length, through holes, connection points, transmission losses, parasitic inductance, etc.
What to Consider When Selecting a Flexible PCB For a Certain Application
(A team of computer engineers selecting a flexible for a certain application)
Many PCBs around the globe suit certain applications rather than others. But first, you should consider whether you’re using it for a static or dynamic application. Static application or flex-to-fit application is when the board has minimal flexing movement.
Consequently, they only flex for easier installation. On the other hand, the dynamic application of flex PCB is in systems that flex daily. In today’s section, we consider what to consider before selecting a PCB for a certain application.
Material: Your choice of material for a flexible PCB will determine its weight and sometimes the overall performance. Some materials have excellent temperature range and chemical resistance, while others do not.
Circuit layout: Depending on the application, look for a flex PCB with a layout design that minimizes signal interference. Flex circuit boards are delicate, meaning that they have little manufacturing tolerances. Any design mistakes will affect their overall performance.
Environmental conditions: Always consider the environment to installing your flexible PCB. By design, the circuit boards have different design parameters that suit certain environments and not others. For example, military vehicles use a flex circuit board with excellent thermal performance for reliability.
What are the Advantages of Using Flexible PCBs in Various Applications
- 360° flexibility, bendability, and durability
- High shock and vibration resistance
- Lightweight structure
- HDI capability
- Can be interfaced with rigid boards to eliminate bulky connectors and reduce testing/assembly costs
- Good electromagnetic immunity and operating temperature range (depending on the material used)
- Can replace cables while taking up less space
Flexible PCB Applications FAQs
What are the Disadvantages of Flexible Circuit Boards?
Some disadvantages of flex PCBs include the following:
- A High initial cost of design and manufacturing
- Flexible PCBs are difficult to change and repair
- The boards have size limitations
- They can easily get damaged when you handle them poorly
Can I Replace a Rigid PCB with a Flexible PCB?
Sometimes, you can replace a rigid PCB with a flexible one. However, it would be best if you considered the board’s design parameters and mechanical constraints.
Other factors include manufacturing constraints and environmental factors. Considering these aspects, you should clearly understand whether to replace one with the other.
Conclusion
The bendable nature of flexible PCBs is their biggest strength because it makes them versatile enough to use in multiple applications. Coupled with their lightweight, low-profile structure, HDI capability, and possible interfacing with rigid boards, flex PCBs can be used in almost all electronics projects.
The only major setback is high production costs. However, continued innovations and explorations in this field can lower these costs and unlock more possibilities in the future.
In the meantime, these boards are a must-have in wearables, military equipment, aerospace, IoT, and other devices, and we can build them for you for such projects at reasonable costs.
Contact us with your project details or product designs, and we’ll be in touch with all the details you need to get started, including a quote.
