IPC International Community magazine an association member publication
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94 I-CONNECT007 MAGAZINE I JULY 2026 What's the first design challenge that comes to mind when you're working with LED displays? Thermal management is one of the biggest. Wheth- er you're designing an LED light bulb, a consumer display, or a large outdoor video board, LEDs gener- ate heat that must be dissipated to maintain perfor- mance and reliability. As power levels and display sizes increase, designers have to think carefully about substrate materials, power delivery, cooling, and overall system design. That's why you'll often see aluminum-core PCBs or other thermal management techniques in high- power LED applications. The challenge isn't the LED itself. Instead, it's about getting the heat away from it efficiently. The challenge simply scales up for large stadium displays: Many high-power LEDs need to be bright enough to be seen on a sunny day, but how do you dissipate the heat? How are we dealing with all the thermal and power control, even more than the LED technology itself? All these must be considered at the level of system and PCB design. What other special design considerations are there when designing PCBs for LED boards? One key design issue is parts placement. For ex- ample, when designing a large display board for scrolling marquee signage, where the entire board is visible, IPC standards allow a certain amount of placement tolerance. That's fine for standard cir- cuitry, but in display circuitry, and LED specifically, pixels must be placed exactly, which makes the sol- dering process so challenging. Density is another big challenge in the design process. That's certainly a common theme, isn't it? Yes, and it's specifically problematic here. For dis- plays smaller than a cellphone screen that require high-resolution graphics, each LED must be mount- ed directly on the board. But how do you fit that many LEDs together while still routing traces or vias to each one without forcing the LEDs farther apart? How do they get soldered? This leads most companies to purchase commer- cially manufactured LED display modules. Rather than placing thousands of discrete LEDs, manu- facturers fabricate the entire LED array as a single display assembly using processes more closely aligned with semiconductor fabrication. We can go through the same process but fabricate the complete LED array into its own ready-to-use package. That's how we typically get LED-based cellphone displays. It is a single fabrication process that now resembles silicon or IC chip fabrication. It becomes easier for the designer to simply buy an off-the-shelf display that connects to your board on your display driver. You can buy these displays with or without their own interposer or controller board. Overall, it has made the design process more streamlined and easier for PCB designers. Given how pervasive displays are, how likely will today's PCB designer encounter a display design at some point in their career? Very likely, especially in consumer goods, avionics, and aerospace products. You probably won't see this in power electronics for a motor or similar tech- nology, but most board designers will encounter some form of display technology. Thermal management and placement are chal- lenges that designers often think about. One that's less obvious is controlling the light itself. What is light bleed, and why does it matter? Light bleed occurs when light from one LED spills into an adjacent viewing area instead of staying confined to its intended indicator or display ele- ment. Imagine a simple 4x4 LED array. Each LED may represent a different function. When one turns on, you don't want that light leaking into the neigh- boring windows. Preventing that requires more than PCB layout. It also requires close coordination with the mechanical design. Display electronics are among the applications where PCB designers have to work closely with the mechanical team. Good electrical design isn't enough. You also have to think about how the light is controlled once it leaves the board. It sounds like you would need some shielding, but what does that look like on that scale and with so much light power being emitted? A light pipe is an old-school technology that uses a molded rigid plastic component. When you have a