Ever since the introduction of circuit boards, they have been evolving. They started as single sided, graduating to double-sided with plated through holes. Shortly thereafter multilayer circuit boards were introduced. The evolution didn’t stop there. New substrates began to come to the market with improved electrical and mechanical properties allowing designers to create denser designs on smaller platforms.
As time went by, around the 1970s, the need for smaller features became the norm, mainly driven by consumer demand. They began appearing in digital watches and early video games. The 1980s drove the demand with CD players, alarm clock radios, video recorders. By the 1990s the evolution rapidly increased for even smaller circuit boards. From early 2000 to today, cell phone production, wearable devices, and implantable devices escalated the demand.
Flexible circuits made their introduction in the late 1950s driven by avionic and aerospace due to their need for a smaller lighter weight replacement for wire harnesses. Defense engineers began experimenting with conductive inks printed on flexible substrates. This gave them light weight and moldable circuits. Like the rigid circuit boards flexible circuits evolved but didn’t really become mainstream until 1980s-1990s. The advancements in base material, particularly with the development of polyimide films allowed more versatility due to its excellent thermal stability and mechanical properties. The miniaturization of flexible circuits drove the industry to develop machinery and processes to support the demand.
The miniaturization of circuit boards has continued to date, for example: the phone. The photo below illustrates how in a little over 40 years the portable phone has evolved from a solid body structure to a flip phone requiring flexible circuits. Today’s phones use flexible circuits because of the weight.
In addition to products components became smaller enabling circuit boards to become smaller. The illustrations below depict how small some of components used today have become.
An interesting evolution has been occurring. The medical field has recognized that flexible circuits could replace fine wires in catheters and endoscopes. The wires are cumbersome and difficult to manage and handle when building a catheter or endoscope. Flexible circuits can contain more signals due to the ability to be multi-layer. Another benefit is components like cameras and others can be pre-mounted prior to inserting into the tubular housing. The pictures below are an example of a long flex for a catheter and a tip of a catheter next to a quarter for scale.
The one obstacle being encountered is the need for longer circuits (1+ meters) and finding circuit board manufacturers capable of building them. This is quite the opposite of the shrinking and miniaturization seen for the last 40 plus years. While the physical size is increasing, the circuitry required is remaining miniature (50µm and below). This combination of small circuits on long platform flexible circuit boards can spell disaster for a manufacturer, especially if not equipped with proper processes and machinery.
The processing involved requires the ability to drill, plate, image, inspect, press, and handling of the panels required for long flexible circuits. For an ordinary facility the implementation of these processes and machinery can be an insurmountable hurdle for both space and cost. With that, there are many manufacturers currently incapable of producing this type of product. While the demand is increasing the supply chain is lagging.
Flexible Circuit Technologies had the foresight years back to recognize the trend and has been investing in the necessary equipment and processes to provide the industry with longer format flexible circuits. In addition to the current capabilities, Flexible Circuit Technologies (FCT) will be investing in additional equipment and processes to allow for the mass production of these types of flexible circuits for future demand.
In addition to having the ability to produce the long format circuits, FCT also can provide flexible and rigid flex circuits, heaters, and an array of other products. We also can provide assembly including complete box builds at our EMS group InTFlex.
Contact us and work with our Applications Engineering team to get started.
