In the pictures of a SMPS of a Blu-Ray player below there are three "cuts" in the PCB under three components. 1 is under something that could be an opto-coupler (IC102), 2 and 3 are under capacitors (C111, C102). I have seen these before and I don't quite understand their function. I've tried to google around but I don't know how to describe these things and I only get literature about through-holes, mounting holes, vias, air gap layers... none of which is relevant. Would love some info so I could go learn about them.


Thanks!