An optical sensing device for detecting plural optical features of valuable papers is provided that comprises first and second photocouplers 5 and 6 or 9 and 10 positioned in the vicinity of and on the opposite sides of a passageway 13 for guiding the valuable paper 64. Each of first and second photocouplers...http://www.google.se/patents/US7677380?utm_source=gb-gplus-sharePatent US7677380 - Optical sensing device for detecting optical features of valuable papers
