LED Display's PCB - Why You Should Pay More Attention

Printed Circuit Board (PCB) mechanically supports and electrically connects components using conductive tracks, pads and other features. If we compare PCB’A function to a busy urban traffic, PCB would be the road infrastructure.

It is the foundation of led display’s quality, efficiency, reliability and durability.

However, when buy led displays, many customers’ due diligence to PCB is not performed enough.

It is also a usual way for the manufacturers who make low cost and inferior led displays, to “cut corner” with using bad quality PCBs.

Their screens may seem good too at the beginning, but would not work properly in just one year or less.

As a result of terrible price competition, to reduce cost, currently many manufacturers use 2 copper layer PCBs, and with very thin copper foil.

It is acceptable to big pitch indoor led displays, but in the case of outdoor fixed led displays, it is gambling!

The PCBs of outdoor led displays are exposed to thermal changes of their working environment. Due to different CTE (coefficient of thermal expansion) between copper and PCB substrate (which is usually FR-4 glass epoxy), the copper expands and contracts 1/4 less than substrate, inducing cyclic fatigue in the copper on circuit traces and vias.

Too thin copper on circuit traces and vias will eventually crack and result electrical open.

And it usually happens months (or even longer) after the installation, and massively!