Apparatus for determining a vertical position of at least one interface between a first component and at least one second component and laboratory automation system

An apparatus for determining a vertical position of at least one interface between a first component and at least one second component comprised as different layers in a sample container, the apparatus comprising:

• a first sensing unit comprising,
• a first laser diode emitting light having a first wavelength transmitted by the sample container and the first component,
• a first collimating optics to collimate the light having the first wavelength, such that the light is emitted in form of a beam having a defined diameter and direction in space, and
• a first light detector generating a first sensing signal in response to an intensity of light having the first wavelength being applied to the first light detector;
• a second sensing unit vertically spaced by a given vertical distance from the first sensing unit comprising,
• a second laser diode emitting light having a second wavelength transmitted by the sample container but blocked by the first component,
• a second collimating optics to collimate the light having the second wavelength such that the light is emitted in form of a beam having a defined diameter and direction in space, wherein the resulting beam having the second wavelength and the resulting beam having the first wavelength propagate in parallel but vertically spaced paths separated by the given vertical distance, and
• a second light detector generating a second sensing signal in response to an intensity of light having the second wavelength being applied to the second light detector;
• a driving unit to move the sample container relative to the first sensing unit and the second sensing unit;
• a position sensing unit to output a position sensing signal indicative of a vertical position of the sample container;
• and
• a vertical position determining unit to match the first sensing signal and the second sensing signal such that first sensing signal and the second sensing signal correspond to identical vertical positions and to determine the vertical position of the at least one interface in response to the matched sensing signals and the position sensing signal.