A potential-separating optical signal transmission device comprises a printed circuit board-based transmitter device with a signal input, a transmission signal conditioning circuit and an optical signal transmitter, a printed circuit board-based receiver device with an optical signal receiver, a received signal processing circuit and a signal output, an optical transmission path between the signal transmitter and the signal receiver, a shield assembly for each transmitter and receiver device, an implementation of the shield assemblies by means of metallic layers in and/or on at least one printed circuit board, and a substantially rigid, transparent transfer rod as an optical transmission path, =the ends of said transfer rod being arranged within the respective shield assembly of the transmitter and receiver device in front of the signal transmitter and signal receiver, respectively, and =being mechanically held by the at least one printed circuit board.