Issue link: https://iconnect007.uberflip.com/i/1369942
96 DESIGN007 MAGAZINE I MAY 2021 per-filled vias are sometimes not completely filled flat or have a small outward dimple. e dents and small dimples are not a problem for the assembler. e use of filled copper vias in flex can greatly increases routing area by free- ing up via pads and spaces. Small dimples on very small pads can cause some assembly headaches since the dimple occupies a large portion of the pad surface. e small bump is usually not an issue, but on very small pads such as 01005 chips and small BGAs, the dimple can pose challenges for the assembler. Sometimes the component assem- bler must modify their tools and processes to deal with the small depressions by adding slightly more solder paste to pads that have a dimple. Everything I have covered to this point assumes multilayer flex. Rigid-flex can also uti- lize via-in-pad, and depending upon the appli- cation and material stack, the fill method can vary by design. For instance, if the rigid cap lay- ers on a rigid-flex are relatively thick (~0.010" +), they need to be filled with conductive resin and planarized like a rigid PCB. inner outer cap layers (0.003" or less) may use the copper plating fill option. For everything between 0.003" and 0.010", it is probably wise to get your flex supplier's input on the best option for your application. FLEX007 John Talbot is president of Tramonto Circuits. To read past columns or contact Talbot, click here. Plastic Logic, a leader in the design and manufac- ture of flexible, glass-free electrophoretic displays (EPDs), has announced a new flexible 5.4in colour display that is set to revolutio- nise smart wearable devices. Smart wearables, such as jew- elry, have become increasingly popular among consumers over the last decade. The problem is most wearable displays are black and white – Plastic Logic is changing all that with its new full- colour display technology. "Wearable device design- ers can now source innova- tive flexible colour display technology to incorporate into applications including smart jewelry, smart cloth- ing and even smart health- tracking devices," said Tim Burne, CEO, Plastic Logic. "Colour really enhances the functionality and look and feel of any smart wearable—in fact, it makes smart wearables even smarter." As well as flexibility, which is key to wearables' design, Plastic Logic's displays are extremely robust as well as ultrathin, lightweight and flexible, making them ideally suited for integration into wearables that need to withstand the wear- and-tear of daily usage. "When it comes to wearable products, we've proved that you don't have to trade visual appeal for functionality," added Tim Burne. "We have already worked with several smart jewelry manufacturers, developing wearable display solutions for their innovative products. There are many more wearable applications that this technology is perfect for." Plastic Logic's displays are avail- able as engineering samples as well as in volume and can be ordered on request. (Source: Plastic Logic) Plastic Logic's Colour Display Revolutionizes Smart Wearables