Flexible Printed Circuits
The ability of flexible printed circuits to bend and fold is the perfect solution for medical devices that need to be compact, lightweight, and versatile. From a wristwatch that can monitor a patient’s heart rate to a device that delivers insulin, the flex PCB has become a mainstay of the modern healthcare industry. As the electronics in these devices continue to shrink, manufacturers must adapt their production methods to accommodate these changes. This means smaller copper traces and spaces, thinner base material, and lower voltages. The challenge of designing for these conditions is well worth it, as it will allow for more innovative and useful products that can help save lives.
In order for a device to be implantable, it must first pass the rigorous FDA approval process. This process usually involves extensive testing on animals and humans to ensure safety and efficacy. This is a vital step, as it will provide the data needed to demonstrate that a specific technology can be effectively translated into medical applications in a clinical setting.
For medical flexible printed circuit, it is essential that the conductive layers are made of a safe material that will not cause damage to human tissue. A wide variety of metal foils can be used for the conductive layers in a flex circuit, however copper is generally preferred due to its excellent balance of cost and physical and electrical performance attributes. Copper also has the advantage of being able to be etched to form the circuit paths. A variety of different copper coatings are available, including hard gold and soft gold, to cover the pads and land termination locations on a flex circuit.
Flexible Printed Circuits for Implantable Medical Devices
Medical flex circuits also require durable materials that can withstand repeated bending and twisting without compromising the integrity of the structure. The most common base material for these types of circuits is polyimide, which provides critical tensile strength and flexibility while remaining chemically stable. This material is also flame retardant and mechanically rigid, making it ideal for the flex PCB’s structural components.
Rigid-flex circuits offer the best of both worlds, as they can be produced in a manner similar to traditional rigid boards while still being flexible. This allows for the use of higher-density connections without the tall and bulky connectors that flat cables require, or even in a hybrid construction that eliminates external connections altogether.
Another benefit of using a flexible printed circuit in a medical device is that it minimizes the number of points of connection, which greatly reduces the likelihood of electronic failure. This is particularly important for devices that are worn or implanted in the body, as points of contact can become a source of stress or fatigue. Flex circuits are also a great choice for wearable medical devices, as they can be designed to bend and move with the user’s body. This enables the device to remain comfortable and functional for longer periods of time. This is especially helpful in the treatment of chronic illnesses and conditions, as patients often require long-term care that will last over a lifetime.