METHOD AND APPARATUS FOR NON-INVASIVE MEASUREMENT OF BLOOD SUGAR LEVEL

摘要

Laser light is periodically intensity and wavelength modulated. This light is separated into two optical paths. One irradiates an examined portion of skin for assessing blood sugar. A first detector detects the intensity of transmitted or reflected light from examined portion, while the intensity of the laser light passing through the second path is detected by a second detector. The ratio of the former intensity to the latter intensity is determined by a logarithmic ratio amplifier. The rate of change in the ratio with respect to the change in wavelength of the wavelength modulation is determined by a lock-in amplifier to obtain a derivative spectral signal of the absorption spectrum of glucose. An arithmetic processor detects the blood sugar in the examined portion from the derivative spectrum.