Sensor System

Abstract

The disclosure relates to a sensor system for detecting a position of a movable plunger in a drug delivery device, the sensor system comprising a sensor capable of detecting a magnetic field, the sensor adapted to be fixed within a housing of a drug delivery device, and a ferromagnetic or permanent magnetic component magnetically interacting with the sensor and adapted to move relative to the sensor as the plunger is moved.

1 . A sensor system for detecting a position of a movable plunger in a drug delivery device, the sensor system comprising:
 a sensor capable of detecting a magnetic field; and   a magnetic component magnetically interacting with the sensor and adapted to move relative to the sensor as the movable plunger is moved.   
     
     
         2 . The sensor system according to  claim 1 , wherein the sensor is arranged in or on the movable plunger. 
     
     
         3 . The sensor system according to  claim 1 , wherein the sensor comprises one or more of an electromagnetic coil, a surface mounted device, a printed circuit, a conductive polymer, a double coil sensor, and a permanent magnetic linear contactless displacement sensor. 
     
     
         4 . The sensor system according to  claim 1 , wherein the sensor is electrically connected to at least two contacts accessible by a control unit to process data acquired by the sensor. 
     
     
         5 . The sensor system according to  claim 1 , wherein the sensor is arranged outside of a drive spring configured to provide a force to the plunger. 
     
     
         6 . The sensor system according to  claim 1 , wherein the magnetic component is a magnetic area in or on the movable plunger. 
     
     
         7 . The sensor system according to  claim 6 , wherein the magnetic area is a permanent magnet embedded in the movable plunger or comprises permanent magnetic particles within a polymer material of the movable plunger. 
     
     
         8 . The sensor system according to  claim 1 , wherein the magnetic component is a drive spring comprising a magnetically permeable material. 
     
     
         9 . A drug delivery device, comprising:
 a housing adapted to receive a medicament cartridge;   a plunger adapted to advance a piston within the medicament cartridge; and
 and a sensor system for detecting a position of the plunger, the sensor system comprising: a sensor capable of detecting a magnetic field, and 
 a magnetic component magnetically interacting with the sensor and adapted to move relative to the sensor as the plunger is moved. 
   
     
     
         10 . The sensor system according to  claim 9 , wherein the sensor is arranged in or on the movable plunger. 
     
     
         11 . The drug delivery device according to  claim 9 , wherein a control unit is arranged in or on the housing. 
     
     
         12 . An add-on device for a drug delivery device, the drug delivery device comprising:
 a housing adapted to receive a medicament cartridge,   a plunger adapted to advance a piston within the medicament cartridge, and   and a sensor system for detecting a position of the plunger, the sensor system comprising:
 a sensor capable of detecting a magnetic field, and 
 a magnetic component magnetically interacting with the sensor and adapted to move relative to the sensor as the plunger is moved, 
   wherein the add-on device is adapted to be coupled to the housing and to be electrically connected to at least two contacts of the drug delivery device, and   wherein the add-on device comprises a control unit.   
     
     
         13 . The add-on device according to  claim 12 , further comprising a sleeve part configured to be arranged over the proximal end of the housing. 
     
     
         14 . The add-on device according to  claim 12 , wherein the control unit comprises a user interface. 
     
     
         15 . The add-on device according to  claim 12 , wherein the control unit is configured to process data acquired by the sensor. 
     
     
         16 . The sensor system according to  claim 1 , wherein the magnetic component comprises a ferromagnetic component. 
     
     
         17 . The sensor system according to  claim 1 , wherein the magnetic component comprises a permanent magnetic component. 
     
     
         18 . The drug delivery device according to  claim 9 , wherein the magnetic component comprises a ferromagnetic component. 
     
     
         19 . The drug delivery device according to  claim 9 , wherein the magnetic component comprises a permanent magnetic component. 
     
     
         20 . The drug delivery device according to  claim 9 , further comprising the medicament cartridge.