Patent ID: 8694067

Claim:
A sensor for determining blood characteristics of a subject, the sensor being attachable to the subject and comprising: an emitter unit configured to emit radiation through the tissue of the subject at a plurality of measurement wavelengths; a detector unit comprising at least a first photo detector and at least a second photo detector that are together adapted to receive the radiation at the plurality of wavelengths and to produce in-vivo measurement signals corresponding to the plurality of measurement wavelengths, the in-vivo measurement signals being indicative of absorption caused by blood of the subject, wherein the first and second photo detectors are mounted so that the optical paths from the emitter unit to the first photo detectors is different from the optical path from the emitter unit to the second photo detector and wherein the first photo detector detects a first subset of the plurality of wavelengths and the second photo detector detects a second subset of the plurality of wavelengths such that the plurality of wavelengths are divided between the first and second photo detectors, wherein the first and second subsets include at least one common wavelength; and a path normalization unit configured to normalize the in-vivo measurement signals to one of the optical paths specific to either the first or second photo detector.