Measurement device for non-invasively determining the concentration of polarising substances

A measurement device for noninvasively determining the concentration of polarizing substances in the human body, comprising:

• a source of monochromatic light;
• and
• means responsive to light from said source for performing both a static extinction measurement and a dynamic polarization measurement to obtain a measurement of the concentration of a predetermined polarizing substance in a selected member of the body;
• said performing means including a detector responsive to light from said source to generate a static excitation measurement signal, a polarizer for receiving monochromatic light from the light source and polarizing the received light, an analyzer responsive to polarized light from the polarizer for producing a dynamic polarization measurement signal indicative of the angle of polarization thereof, at least one of said polarizer and said analyzer being rotatable, means for rotating at least one of the polarizer and analyzer, means for confining light from said polarizer to said analyzer to a distinct light path, means for positioning said selected body member containing said predetermined substance in said light path between the polarizer and the analyzer, angle sensor means for generating a reference signal indicative of influence of the rotating means on angle of polarization without influence of said body member being positioned between the polarizer and the analyzer, means responsive to the dynamic polarization measurement signal and the reference signal for determining the angle of deflection of the polarized signal, and means for determining the concentration from said static excitation measurement signal and said angle of deflection.