IPC International Community magazine an association member publication
Issue link: https://iconnect007.uberflip.com/i/1545855
JULY 2026 I I-CONNECT007 MAGAZINE 95 vertical LED and need the light to go out to the right, you attach the light pipe, and it essentially acts like a fiber-optic guide. There are several ways to deal with this issue, from flexible fiber optics to shielding mechanisms in how you build your enclosure (with ribs that sit between your LEDs) to an enclosure cover very close to your LEDs. Do you have a case example that might help illus- trate this challenge? I had a job with one LCD graphics display and sep- arate LEDs for diagnostics and status. They sat at two heights, so the enclosure cover had to be at the height of the LCD display, but the diagnostic LEDs were so low that we were getting light bleed. We solved it by using light pipe technology. Interesting. What about designing for very small displays? We are seeing a need for an almost HDI-level rout- ing capability. Traditional through-hole via technol- ogy is too large, which forces LEDs farther apart un- less you're trying to create a densely packed group of LEDs without using an off-the-shelf, ready-to-use LED panel display. For the purposes of this discussion, we'll assume that's not happening. Many of today's LED displays are pre-etched, ready- to-go, single-panel, prefabricated. But when you're doing it yourself, you worry about how small a trace you can make, given the thickness of the copper lay- ers to be etched. Designers need to understand the relationship between minimum trace width, via size, starting copper thickness, and manufacturability. That relationship often leads to other problems. To have LED display technology on the same board where you're generating power, you need thick copper for power delivery and very thin copper for fine-line display routing. How do you achieve both in a manufacturable design? A designer must make some conscious tradeoffs. If the only way to achieve the LED density we want for certain display capabilities is to use the high-density footprint, there is a higher risk of assembly-related issues because we have a much smaller solder drop. In a high-reliability environment, a designer and product engineer must consider how to mix high density and high reliability. Ultimately, these deci- sions affect manufacturability, reliability, and cost. You mentioned AR and VR as an emerging catego- ry of display electronics. How is that changing the way designers think about PCB design? AR and VR are interesting because they blur the line between PCB design and semiconductor man- ufacturing. Conductive features have become so small that many of the manufacturing techniques look more like silicon fabrication than traditional PCB fabrication. Most PCB designers won't design AR display glass itself, but they will see more addi- tive manufacturing processes and finer geometries making their way into mainstream PCB design. What does that mean for today's PCB designer? There's now a crossover between silicon and board design disciplines, merging out of necessity. De- signers have to move beyond thinking only about subtractive PCB processes. They need to under- stand when additive manufacturing, like SAP and mSAP, makes sense and how manufacturing capa- bilities influence design decisions. Is this an exciting development for PCB designers, and does it require new designers to have more breadth and depth than in the past? I think it does. Engineers and designers increasingly have to think outside the box to address challeng- es. Solving those engineering and manufacturing challenges is what creates value for customers. The designer who understands the available materials, manufacturing methods, and design techniques is no longer just laying out circuit boards; they're solv- ing complex engineering problems. That broader knowledge makes them a more complete PCB de- signer or engineer and a far more valuable contrib- utor to the product development process. Kristin, you've really helped us better understand the challenges and implications of today's display electronics technology. It's an evolving field, Marcy. Happy to talk about it. I-CONNECT007