Love how all the circuit traces are also transparent and the 2 chips are connected by nothing.
Traces less than a micron thick and wide would be practically invisible to the naked eye. At best, you may notice different shades of grey or transparency depending on how densely packed traces and on-glass electronics are around any given area.
You do not need 2oz copper planes for (ultra-)low-power electronics.
Next time you have a broken digital watch, take it apart to extract the LCD. The connection between the watch's PCB and LCD is usually done using a "rubber bridge" and the electrical contacts on the LCD glass are nearly invisible - you have to tilt the LCD at the right angle relative to your light source to make them visible due to differences in optical properties.