PEN TYPE DRUG INJECTION DEVICE WITH ABSOLUTE ANGULAR DOSE ENCODER MECHANISM

摘要

A pen-type drug injection device (100) comprising a housing (102), a cylindrical member (406) rotatably supported within the housing, and a plurality of sensors (212a-212g) (e.g. electrical contacts linked to a processor), wherein the outer surface of the cylindrical member is provided with a single track (300), the track forming an encoder and having a plurality of first track segments (302) and a plurality of second track segments (304) (e.g. electrically conducting/non-conducting or optically distinct segments) arranged along the length of the track which are respectively capable of inducing first and second responses in the sensors, such that the absolute rotational position of the cylindrical member relative to the housing can be determined.