| 摘要 |
PROBLEM TO BE SOLVED: To obtain information about the concentration of an in-blood substance by a simple method.SOLUTION: A light emitting unit 21 emits light beams λ1, λ2, λ3, λ4 having different N kinds of wavelengths, where N is an integer of four or more. A light receiving unit 22 outputs N kinds of signals S1, S2, S3, S4 according to received light intensities of the N kinds of light beams transmitted through or reflected off a living tissue. A first computation unit 41 acquires N kinds of light attenuations A1, A2, A3, A4 on the basis of the N kinds of signals. A second computation unit 42 acquires (N-1) kinds of blood-derived light attenuations Ab21, Ab23, Ab24 on the basis of two light attenuations (A2-A1), (A2-A3), (A2-A4) related to (N-1) kinds of combinations selected from the N kinds of light attenuations. A third computation unit 43 identifies concentrations O2Hb, RHb, COHb of (N-1) kinds of in-blood substances on the basis of the (N-1) kinds of blood-derived light attenuations. An output unit 14 outputs the identified concentrations. |
