Issue link: https://iconnect007.uberflip.com/i/1475604
80 DESIGN007 MAGAZINE I AUGUST 2022 newer version of a user inter- face. ose can be low vol- ume because of the process of screen printing. And then if you do have it, you can do faster screen-printing equip- ment for high volumes. It's there either way you want it. Shaughnessy: e m a i n u s e f o r printed electron- i c s i s i n m e m - brane touch switches. Bianchi: Right. But that's not the only use; in my opinion, it's the original use and it probably is still used primarily for membrane switches. Other applications are growing faster than applications for membrane switches but that's still our core business—membrane switches and user interfaces. Wagner: Companies like Butler Technologies, and I'm sure Eastprint, leverage their knowledge of how to do circuits or membrane switches into these other printed electronic applications. It was not that hard of a transition for some parts of those printed electronics projects. Bianchi: Right. ere are similar manufactur- ing processes: screen printing, die cutting, lamination, and surface mount. en you go from a membrane switch to a wearable patch or printed heater in a garment. Wagner: From our standpoint, we don't even consider membrane switches as pr inted electronics, just because they've been around so long. It's not cutting edge compared to printed electronics as we think of it. Shaughnessy: Printed electronics cannot do fine line circuits. I've heard that before. Bianchi: I think they can do fine lines, but not as fine as some other circuit technol- ogy. Wagner: I w a s a t t h e I D TechEx conference recently and they were talking about screen printing fine lines. Most people in applications don't necessarily need to print that fine, but people are printing sub-25-micron lines to create transparent heaters or transparent capacitive touch sensors instead of printing things like PDOT or other clear conductors. We can easily print with the right substrate ink. We just did a test for one of the presenta- tions. No problem doing 75-micron lines and spaces and 50 microns with the right combina- tion. It's not that difficult, but it's not that com- mon in certain applications. Miller: ere are specialty inks that the suppli- ers provide if you're doing fine lines. We have many different types of conductive inks, and I know some of our competition does as well. ere are also different types of meshes that take that into account if you're doing fine lines. Bianchi: e one variable is that the finer you go, the less ink you're laying down, and as the resistance changes, how long is the trace, and how big is the part? e current and voltage are all impacted. Wagner: Exactly. at was a big thing. A discus- sion at the workshop was how much current these tiny traces can carry in certain applica- tions. Bianchi: ere are a lot of customer applica- tions we get saying, "We can print at that fine line, but it won't meet the electrical require- ments." So, they have to change the design a little bit to meet the electrical requirements. Mike Wagner