Oxygen-saturation measuring apparatus

Abstract

An apparatus for measuring an oxygen saturation of a living subject, including a light source which emits, toward a tissue of the subject, a first light having a first wavelength whose absorption coefficient with respect to hemoglobin changes depending upon oxygen saturation, and a second light having a second wavelength whose absorption coefficient with respect to hemoglobin does not change depending upon oxygen saturation, a light sensor which detects a secondary light resulting from the first light, and a secondary light resulting from the second light, and produces a first light signal representing the detected secondary light of the first light, and a second light signal representing the detected secondary light of the second light, and an oxygen-saturation determining device for determining the oxygen saturation of the subject, based on a ratio of a magnitude of one of the first and second light signals to a magnitude of the other of the first and second light signals, according to a predetermined linear relationship between oxygen saturation and signal-magnitude ratio. The first wavelength falls in a range of from 720 nm to 740 nm and the second wavelength falls in a range of from 800 nm to 840 nm.

Dependencies are inferred from the claim text.