An optical sensor for a delivery device having a piston that displaces a substance, such as a fluid, from a reservoir. The optical sensor has a light source and a detector array for imaging encoding features disposed along a plunger rod coupled to the piston. By virtue of the pattern of encoding features,...http://www.google.de/patents/US7498563?utm_source=gb-gplus-sharePatent US7498563 - Optical displacement sensor for infusion devices
