Patent ID: 8383327

Claim:
A method for producing an electro-optical printed circuit board, the board including an optical waveguide structure having a transparent bottom layer disposed over a substrate, a transparent core layer disposed over the bottom layer, and a cladding layer disposed over the core layer, the method comprising: forming a non-transparent area consisting of a non-transparent material on the substrate; applying the bottom layer to the substrate so that the bottom layer does not cover the non-transparent area; applying the core layer so that the core layer covers the bottom layer and the non-transparent area; structuring the core layer by exposing to electromagnetic radiation through a single exposure mask and subsequently removing non-exposed portions of the core layer so as to leave exposed portions of the core layer remaining on the bottom layer as part of the waveguide structure and to leave exposed portions of the core layer remaining on the non-transparent area forming a structured region, applying the cladding layer so that the cladding layer does not cover the at least one opening of the structured region, and removing material from the non-transparent area within the structured region for forming at least one reference mark.