US Patent 11553598 Integrated electro-optical flexible circuit board

An integrated electro-optical circuit board comprises a first flexible substrate having a top side and a bottom side, at least one first optical circuit on the bottom side of the first flexible substrate connected to the top surface through a filled via, at least one first metal trace on the top side of the first flexible substrate, an optical adhesive layer connecting the bottom side of the first flexible substrate to a top side of a second flexible substrate, and at least one second metal trace on a bottom side of the second flexible substrate connected by a filled via through the second flexible substrate, the optical adhesive layer, and the first flexible substrate to the at least one first metal trace.