Optical determination of the position of the stopper in glass ampoules
A method for determining a position of a component in a medical apparatus along a travel distance. The method comprising the steps of generating light by a light source; fixing the component movably along a travel distance; providing a photosensitive sensor surface, and generating a silhouette of the component on the sensor surface by irradiating the component with light from the light source. Data relating to the silhouette is converted by a data processing unit into the position of the component along the travel distance. The component whose position is determined may comprise a stopper of a cartridge.
1. A method for determining the position of a component of a medical apparatus along a travel distance by means of
a) a light source comprising an LED row,
b) a holder that fixes the component movably along a travel distance,
c) a photosensitive surface of a sensor, and
d) a data processing unit,
wherein the method comprises:
initially generating a silhouette of the component on the photosensitive surface by irradiating the component with light from the light source to create a first region of the photosensitive surface irradiated with light having a first intensity and a second region of the photosensitive surface irradiated with light having a second intensity, wherein the second intensity is greater than the first intensity, wherein the medical apparatus is configured such that light resulting from irradiating the component that reaches the photosensitive surface of the sensor did not pass through a lens between the holder and the photosensitive surface, and wherein the component is a solid component;
determining a boundary between the first region of the photosensitive surface and the second region of the photosensitive surface;
determining a location of the boundary on the photosensitive surface; and
converting, using the data processing unit, the location of the boundary on the photosensitive surface into the position of the component of the medical apparatus along the travel distance.
2. The method as claimed in claim 1 , wherein the component of the medical apparatus whose position is determined is a stopper of a cartridge for a pharmaceutical, or a component connected to a stopper of a cartridge for a pharmaceutical.
3. The method as claimed in claim 2 , wherein the pharmaceutical is insulin.
4. The method as claimed in claim 2 , wherein the light source transilluminates the cartridge.
5. The method as claimed in claim 4 , wherein the data processing unit determines whether a portion of the cartridge is full or empty based on the second intensity of light on the second region of the photosensitive surface.
6. The method as claimed in claim 1 , wherein the component whose position is to be determined relates to an adjusting device used to preset an amount of a pharmaceutical to be delivered.
7. The method as claimed in claim 1 , wherein the component whose position is determined relates to a feed unit for removing a pharmaceutical from a cartridge.
8. The method as claimed in claim 1 , wherein the data processing unit is integrated in the medical apparatus.
9. The method as claimed in claim 1 , wherein a separate data processing unit is operated together with the medical apparatus.
10. The method as claimed in claim 1 , wherein an aperture is disposed between the light source and the holder, and a second aperture between the holder and the photosensitive surface.
11. The method as claimed in claim 1 , wherein an aperture is disposed between the light source and the holder, or is disposed between the holder and the photosensitive surface.
12. The method as claimed in claim 1 , wherein the LED row gives a diffuse beam.
13. The method as claimed in claim 1 , wherein each individual LED of the LED row has a small aperture angle.
14. The method as claimed in claim 1 , wherein a converging lens is disposed between the LED row and the component.
15. The method as claimed in claim 14 , wherein the converging lens is a cylindrical lens.
16. The method as claimed in claim 1 , wherein the light source generates red light.
17. The method as claimed in claim 1 , wherein the photosensitive surface comprises a row of arranged sensor elements.
18. The method as claimed in claim 17 , wherein the sensitivity of the row of arranged sensor elements is greatest with red light.
19. The method as claimed in claim 1 , wherein the sensor is a line-scan sensor.
20. The method as claimed in claim 1 , wherein the first intensity is zero or substantially zero.
21. The method as claimed in claim 1 , wherein a slit is disposed between the light source and the component.
22. The method as claimed in claim 1 , wherein the holder comprises a sidewall of a cartridge in which the component is disposed.