Apparatus for determining the concentration of a light-absorbing material in blood

摘要

An apparatus for determining the concentration of a light-absorbing material contained in blood flowing through a tissue which minimizes the amount of error caused by noise and which ensures highly precise results at all times. The apparatus operates according the principle that light beams of different wavelengths are absorbed by different amounts when passing through the tissue at different portions of the blood pulsation cycle. A plurality of points are detected that fall in the vicinity of the peak and trough of a cycle of a light detection signal. For each wavelength of light, the values of the detection signals produced at each of these points in time is stored. The concentration of the light-absorbing material is computed in response to the stored detection signals.