Issue link: https://iconnect007.uberflip.com/i/1129312
34 PCB007 MAGAZINE I JUNE 2019 "Everything you imagine is real," is a well- known, inspirational quote by Pablo Picasso of- ten interpreted in the context of the power of the imagination. This phrase parallels something I find true in flex and rigid-flex design. Often, the applications for flexible circuits are simply limited by our imagination. One of the favor - ite parts of my job are the days when I meet with a group of engineers and designers to talk about flex and rigid-flex. We might do a "lunch and learn" with a general overview of the tech - nology or address a specific challenge. It is al- ways helpful to bring samples to pass around and show different features. Usually, looking at a sample will spark an idea and the comment, "I wonder if we could do something like this." From there, the brainstorming begins. Knowing this month's theme was going to be "everything starts with design" made me wonder if I could make something similar hap- pen by looking at pictures rather than holding flex and rigid-flex in your hands. If these pic- tures help generate an idea for a new design, I would love to hear about it. If not, I will point Spark an Idea out some of the best practices being utilized in these designs that should be beneficial to those new to flex and design—and maybe a good re- minder to those more experienced. Let's start with a basic flex design. Figure 1 is a straightforward, single-sided design connect- ing two components. I imagine this could re- place wire and save space and weight. It could also replace a rigid board and solve a pack- aging issue. The FR-4 stiffeners are important here to support the weight of a heavier com- ponent and prevent damage to the flex circuit. Figure 2 is a double-sided flex, using a com- bination of through-hole and SMT compo- nents. In this image, you can see the polyimide stiffener in the tail area. Zero insertion force) (ZIF) connectors are a common termination method for flex and require tight tolerances for both the outline and the overall thickness. Polyimide stiffeners are commonly used to in- crease the thickness to meet this specification. Flex Talk Feature Column by Tara Dunn, OMNI PCB Figure 1. Figure 2.