I want to build a combined diffused light and touch-button around 3x3cm. LEDs could be diffused with e.g. a polycarbonate sheet or diffusing fabric, and touch could be sensed e.g. through capacitive touch sensing.
But how could I combine these two for the same button? I haven't been able to find a diffusing material that is also conductive, which (if I've understood correctly) would be necessary to use capacitive sensing. I could have a tiny copper lead in the middle of the button for touch sensing, but I'd like it to be possible to touch not just in the dead center, but on most of the button.
How could I solve this problem?