Although we are not even done with the shematics, we wanted to figure out how much space we will have left on the PCB once the LED are routed. Indeed, since we can’t use blind vias, and must cross columns/rows signals, we know we are going to create a vias matrix.
Thus, it will be hard to use the back of the LED panel other than for routing, or placing small components. In particular, the SoM’s connectors aren’t probably going to fit.
Taking inspiration from one of TI’s reference design, I tried to do a minimal routing of the LEDs only. Using NFC 93-713 class 5, I managed to place a LED each 2.7mm. RGB cathodes are routed on the surface, and anodes are routed in a medium layer using vias.
The good news are:
- We can have a really small-pitch screen.
- We have a lot of free space on the PCB. The minimum LED panel size is roughly 11 x 9cm whereas the PCB’s height is 19cm.
I will need to check with the other components we need, but I’m quite confident that we can avoid using an extra horizontal PCB.