Patent ID: 7991447

Claim:
Biological photometric equipment comprising: a light irradiating unit for irradiating a trial subject with mixed light obtained by mixing light in a first wavelength range having a peak wavelength at a first wavelength and light in a second wavelength range having a peak wavelength at a wavelength longer than the first wavelength; and a light receiving unit, adapted to be disposed on said trial subject, for detecting transmitted light irradiated from said light irradiating unit and propagating into the inside of said trial subject; wherein a value of said first wavelength is in the range from 650 nm to 800 nm and a value of said second wavelength is in the range from 810 nm to 900 nm; wherein a unit for changing a ratio of irradiated light intensities for measuring biological information concerning density of a light-absorbing material or changes in the densities in said trial subject is measured based on transmitted signals detected by said light receiving unit; wherein the unit for changing a ratio of irradiated light intensities maintains a sum of intensity of the irradiated light in said first wavelength range at a region X on the trial subject irradiated with the light and intensity of the irradiated light in said second wavelength range is kept not higher than a prespecified value; and wherein said intensity of irradiated light in said first wavelength range at said region X is at least either in the range from 0.3 to 0.7 times or in the range from 1.3 to 19 times as compared to that of irradiated light in said, second wavelength range.