An apparatus for measuring a concentration of a light-absorbing substance in blood is disclosed. A light emitter emits light beams to irradiate a living tissue, each of the light beams being associated with one wavelength which is absorbed by the blood. A first instrument measures first intensities of...http://www.google.de/patents/US7257433?utm_source=gb-gplus-sharePatent US7257433 - Apparatus for measuring concentration of light-absorbing substance in blood
