Patent attributes
The invention relates to: A medication delivery device (1) for delivering a specific dose comprising a medication cartridge (11) having an outlet (111) and a piston (112), and means (12) for holding said cartridge, and a piston rod (13) being operable to engage and displace said piston, and electrically driven actuating means (15), and driving means (161, 162) for transferring movement from said actuating means to said piston rod, and memory means (17) for storing data, and processing means (18) for evaluating said data and for controlling said actuating means. The object of the present invention is to provide a medication delivery system that combines a relatively high dose accuracy with the use of relatively low quality mechanical components and which enables compensation for built-in non-linearities. The problem is solved in that a first set of data (19) describing the actual movement (130) of said piston rod (13) relative to said medication cartridge (11) as a function of the movement (150) of said actuating means (15) is stored in said memory means (17), and the movement (130) of the piston rod (13) governing the delivered dose is controlled by the processing means (18) on the basis of said first set of data (19). This has the advantage of allowing compensation for mechanical inaccuracies and built-in non-linearities linearities. The invention may e.g. be used in injection or infusion devices for a person's self-treatment of a disease such as diabetes.
