MEASURING SYSTEM OF REFLECTANCE OF LIGHT

PURPOSE:To measure precisely the reflectance by measuring a light flux of single wavelength produced from a spectroscope as the output and transmitted through a beam splitter and a light flux bent by 90 degree, a light flux, etc. obtained by bending by 90 degree by a splitter the reflected light of the sample on the light axis of the transmitted light flux. CONSTITUTION:The light flux of single wavelength light from the spectroscope 11 is measured by PM13 (PM is photomultiplier tube) and the value is defined as I1, and the values obtained by measuring the fluxes of the light transmitted through the beam splitter 21 and the light whose direction is bent by 90 degree are defined as I2, I3 respectively. A sample 31 to be measured is set on the axis of the light passed through the splitter 21, and the reflected light impinged at the sample 31 is furthermore bent by 90 degree by the splitter 21, and the light flux thereof is measured by PM13 and the value is defined as I4. Thus the reflectance R of the perpendicular incident light to the sample 31 is obtained from I1.I4/I2.I3 and the precise reflectance can be obtained.