| 摘要 |
A laser beam, the wavelength of which is modulated periodically, emitted from a variable-wavelength semiconductor laser (11) is intensity-modulated periodically by an attenuator (12). This laser beam is separated into optical paths (13a, 13b) by a beam splitter (14) and applied via the optical path (13a) to a portion (17) at which a blood sugar level is to be measured. The intensity of the transmitting light through or reflected light of the object portion (17) and that of a laser beam in the optical path (13b) are detected by first and second detectors (21, 22) respectively, and a ratio of one of the intensities to the other is detected by a logarithmic ratio amplifier (25). A variation ratio of this ratio to a variation of a wavelength modulating wavelength is detected by a lock-in amplifier (26), and a differential spectrum signal of the absorption spectrum of glucose at the object portion is taken out from this variation rate. An arithmetic processing unit (27) is adapted to detect a blood sugar level of the object portion on the basis of this differential spectrum signal. <IMAGE> |
