Flexible circuit boards, also known as flex PCBs, have become increasingly popular due to their ability to bend and twist, making them suitable for use in a wide range of applications.
However, when it comes to connecting them to other components, choosing the right connector option can be challenging.
In this article, we’ll explore the different connector options available for flexible circuit boards and provide guidance on how to choose the best one for your needs.
What is Flexible Circuit Boards Connector?
Flex PCBs and other electronic components are connected electrically by use of flexible circuit board connectors.
These connectors are designed to accommodate the flexibility and thinness of the flex PCBs while providing a secure and reliable connection.
Depending on the needs of the application, flexible circuit board connectors are available in a variety of styles, dimensions, and forms. They play a critical role in enabling the use of flex PCBs in a wide range of industries.
Flexible Circuit Boards Connector
What are Flexible Circuit Boards Connectors used for?
Flexible circuit board connectors support the flexibility and thinness of flex PCBs and offer a dependable and secure connection.
They come in various types, shapes, and sizes, depending on the application requirements.
Some common uses of flexible circuit board connectors include connecting flex PCBs to displays, batteries, sensors, and other electronic components in a wide range of devices such as smartphones, laptops, wearables, and medical implants.
How Does Flexible Circuit Boards Connector Work?
Flexible circuit board connectors work by establishing electrical connections between the conductive traces on a flexible printed circuit board (flex PCB) and the corresponding contacts on another electronic component, such as a display or a sensor.
The connector is designed to accommodate the flexibility and thinness of the flex PCB while providing a secure and reliable connection.
Depending on the type of connector, it may feature a spring mechanism, locking mechanism, or compression mechanism that holds the flex PCB in place and ensures a stable electrical connection.
The connector’s contacts may be arranged in different configurations, such as surface mount or through-hole, depending on the application requirements.
The contacts may also be made from various materials, such as gold or nickel, to provide optimal conductivity and corrosion resistance.
Types of Flexible Circuit Boards Connector
Flexible circuit board connectors come in a variety of types, each with their own unique features and benefits. Some of the most common types of flexible circuit board connectors include:
ZIF Connectors
A popular type of flexible circuit board connector that require no force to insert or remove the flex PCB. Instead, they use a spring mechanism that gently clamps the flex PCB in place, making them ideal for applications where the flex PCB may need to be inserted or removed frequently.
ZIF Connectors
Non-ZIF Connectors
A type of flexible circuit board connector that requires some force to insert or remove the flex PCB. These connectors typically feature a locking mechanism that secures the flex PCB in place, ensuring a stable and reliable connection.
Non-ZIF Connectors
Interposer Connectors
A type of flexible circuit board connector that use an intermediate component, known as an interposer, to establish electrical connections between the flex PCB and other electronic components. These connectors are commonly used in applications where the spacing between the flex PCB and other components is too large to accommodate a direct connection.
Interposer Connectors
Male / Female Connectors
A common type of flexible circuit board connector that feature male and female contact points. The male connector is typically mounted on the flex PCB, while the female connector is mounted on the other component. When the connectors are mated, the contact points establish an electrical connection.
Male / Female Connectors
Crimp Connectors
Uses a mechanical crimping process to establish an electrical connection between the flex PCB and other electronic components. These connectors are commonly used in applications where a soldered connection is not possible or desirable.
Crimp Connectors
Solder Attached Connectors
Uses solder to establish an electrical connection between the flex PCB and other electronic components. These connectors are commonly used in applications where a strong and reliable connection is required.
Solder Attached Connectors
Insertion Connectors
A type of flexible circuit board connector that require the flex PCB to be inserted into the connector manually. These connectors typically feature a locking mechanism that secures the flex PCB in place, ensuring a stable and reliable connection.
Insertion Connectors
Z-Axis Connectors
Uses a vertical orientation to establish electrical connections between the flex PCB and other electronic components. These connectors are commonly used in applications where space is limited, and a horizontal orientation is not feasible.
Z-Axis Connectors
Sculptured Connectors
Features a contoured design that conforms to the shape of the flex PCB. These connectors are commonly used in applications where the flex PCB has an irregular shape or curvature, and a standard connector is not suitable.
Sculptured Connectors
Vital Parts of Flexible Circuit Boards Connector
Flexible circuit board connectors consist of several vital parts that work together to establish a reliable and secure electrical connection between the flex PCB and other electronic components. Some of the most important parts of a flexible circuit board connector include:
Terminal
The terminal is the part of the connector that establishes the electrical connection between the flex PCB and other electronic components. Terminals are typically made from copper or other conductive materials and are designed to provide a reliable and consistent connection.
Plastic Body
The plastic body of the connector provides support and protection for the terminal and helps to maintain the proper spacing between the flex PCB and other components. The plastic body is typically made from high-quality materials that are durable and resistant to damage from temperature changes, moisture, and other environmental factors.
Card Lock
The card lock is a locking mechanism that secures the flex PCB in place within the connector. Card locks can be either ZIF or non-ZIF and are designed to provide a secure and reliable connection without requiring excessive force. ZIF card locks use a spring mechanism to clamp the flex PCB in place, while non-ZIF card locks use a locking mechanism that requires manual engagement and disengagement.
Flexible Circuit Boards Connector
Important Features of Flexible Circuit Boards Connector
Flexible circuit board connectors are critical components used in various applications, and they come with several essential features. These features include a low profile, high-speed performance, high-temperature resistance, EMI/RFI shielding, flexibility, and durability.
The low profile feature of these connectors makes them ideal for use in applications where space is limited. High-speed performance connectors are designed for applications requiring high-speed data transfer.
High-temperature resistance is critical in automotive, aerospace, and military applications. EMI/RFI shielding connectors can protect sensitive electronics from interference. The flexibility of these connectors allows them to be bent and shaped to fit specific applications, and durability ensures they are resistant to environmental factors.
In summary, selecting the right flexible circuit board connectors with the appropriate features for a specific application is essential for ensuring optimal performance and reliability.
Advantages of Flexible PCB Connector
One of the primary advantages is their flexibility, which allows them to bend and conform to the shape of the device, making them ideal for use in applications where space is at a premium. They are also lightweight, which can reduce the overall weight of the device and provide design flexibility.
In addition to having a reduced profile, flexible PCB connections are more adaptable and simpler to employ in small devices. They also offer better vibration resistance and shock absorption, which is critical in applications where reliability is essential.
Finally, flexible PCB connectors are easier to assemble and can be customized to specific applications, reducing assembly time and costs. Overall, flexible PCB connectors are a popular option in a variety of sectors and applications due to their benefits.
How Does a Board-To-FPC Connection Work?
A Board-To-FPC (Flexible Printed Circuit) connection is a method of connecting a rigid printed circuit board (PCB) to a flexible printed circuit (FPC) using a connector.
The process involves selecting the right connector for the specific application, preparing both the FPC and PCB, and attaching the connector to the PCB by soldering or press-fitting it onto the contact pads. Once the connector is attached, the FPC is inserted into the connector and secured using a latch or lock mechanism.
Finally, the connection is tested for continuity and functionality to ensure it meets the required specifications. Overall, a Board-To-FPC connection is a simple process, but it requires careful attention to detail to ensure a reliable and efficient connection.
Board-To-FPC
Materials Used in Flexible Circuit Boards Connector Manufacturing
The following are the main materials used in manufacturing flex PCBs:
Insulating Material
Insulating materials are used in flexible circuit board connector manufacturing to isolate conductive pathways and prevent electrical shorts. Common insulating materials used include polyimide, polyester, and PTFE.
Adhesive Material
Adhesive materials are used in flexible circuit board connector manufacturing to bond the layers of the flexible PCB together. Common adhesive materials used include acrylic, epoxy, and polyurethane.
Conductive Material
Conductive materials are used in flexible circuit board connector manufacturing to create the electrical pathways required for the device to function. Common conductive materials used include copper, silver, and gold.
Flexible Material
Flexible materials are the foundation of flexible circuit board connectors. They are used to create the flexible circuit board substrate and allow the connector to bend and conform to the shape of the device.
Things to Consider in Choosing a Flexible Circuit Boards Connector
The following are few important factors to consider when choosing your Flex PCB connectors:
Cost
The cost of a flexible circuit board connector is an important factor to consider in choosing the right connector. The cost will depend on the materials used, manufacturing process, and complexity of the connector.
Mechanical Strength
Refers to the ability of the flexible circuit board connector to withstand physical stress and deformation without breaking. It is important to consider the mechanical strength of the connector to ensure its reliability and durability.
Density of Connection
Refers to the number of connection points per unit area of the connector. A higher density of connection can increase the functionality of the device, but it may also increase the complexity and cost of the connector.
Number of Connection Points
Refers to the number of electrical connections required for the device to function. It is important to consider the number of connection points to ensure that the connector has the required number of pins or contacts.
Substrate Thickness
The substrate thickness of the flexible circuit board connector is an important consideration in choosing the right connector. It affects the flexibility and durability of the connector.
Conductor Thickness
The conductor thickness of the flexible circuit board connector affects the electrical performance of the device. It is important to consider the conductor thickness to ensure that it can handle the required current and voltage levels.
Mount Orientation
Refers to the direction in which the connector is mounted on the device. It is important to consider the mount orientation to ensure that the connector can be easily accessed and connected.
FPC Actuator Type
The FPC actuator type of the flexible circuit board connector refers to the mechanism used to secure the FPC in place. It is important to consider the FPC actuator type to ensure that it is compatible with the FPC and can securely hold it in place.
Front Flip
The FPC is inserted into the connector and then flipped over a locking mechanism on the front of the connector to secure it in place. This type of actuator is commonly used when space is limited and the connector needs to be located close to other components.
Rear Flip
Similar to the front flip, but the locking mechanism is located on the back of the connector. This type of actuator is commonly used when there is more space available on the back of the connector and the locking mechanism can be larger.
Stuffer / Plunger Style
The FPC is inserted into the connector and a plunger or stuffer mechanism is used to secure it in place. This type of actuator is commonly used when the connector needs to be mated and unmated frequently and needs a quick and easy locking mechanism.
Contact Mating Area Plating
It is important to consider the contact mating area plating to ensure that it can handle the required current and voltage levels and is compatible with the mating contact material.
Gold
a common choice for contact mating area plating, as it is highly resistant to corrosion and oxidation. It also offers good conductivity and durability, making it ideal for use in applications that require frequent mating and unmating.
Gold Flash
A thinner layer of gold plating that is applied to the contact mating area. It is a cost-effective alternative to full gold plating and still provides good conductivity and corrosion resistance.
Tin
A common choice for contact mating area plating as it is cost-effective and provides good conductivity. However, it is less resistant to corrosion than gold plating.
Tin-Lead
A mixture of tin and lead that is used as an alternative to tin plating. It provides better solderability and improved corrosion resistance compared to pure tin plating.
Choosing a Flexible Circuit Boards Connector
Ways to Test Flexible Circuit Boards Connector
There are several ways to test flexible circuit board connectors to ensure their performance and functionality, including:
Burn-In Testing
This type of testing involves exposing the connector to extreme temperatures and voltage to detect any issues that may arise over time. Burn-in testing is especially useful for testing connectors used in high-stress applications.
AOI Inspection
Automated Optical Inspection (AOI) is a non-destructive testing method that uses advanced imaging techniques to inspect the connector for defects, such as scratches, misalignments, and other surface imperfections.
Flying Probe Testing
This type of testing involves using specialized equipment to test the electrical connectivity of the connector. It is a non-invasive and automated testing method that is ideal for testing complex connectors with multiple pins.
ICT Testing
In-Circuit Testing (ICT) is a testing method that verifies the electrical connectivity of the connector while it is in use. This type of testing is useful for identifying problems related to signal integrity, voltage drops, and other electrical issues.
