REFLECTANCE MEASURING APPARATUS

PURPOSE:To minimize measuring errors due to yearly changes in a reference sample and a structural difference of equipment, by arranging an absolute reflectance measuring mechanism and a relative reflectance measuring mechanism. CONSTITUTION:A sample light 3 from a spectroscope 1 is reflected with a toroidal mirror 4 by 90 deg. and again by 90 deg. with a toroidal mirror 5 to be converged into a lens 6 and enters an absolute reflectance measuring mechanism 60. Here, the dotted line is indicates a measurement of a reference sample with a relative reflectance measuring machine. Electrical signals of a sample light 2 and a control light 3 are transmitted to a data processing section 13 on the side of a spectroscope 1. Correction factors of the sample light 2 and the control light 3 are stored into a memory in a terms of wavelength. For use as absolute reflectance measuring device, a reference sample 65 is set. A reference mirror 62 is set for 62' and a rotary mirror 63 for 63'. With such an arrangement, the absolute value of a surface reflection of the sample 65 is measured. This value is stored into other area than the correction factors in terms of wavelength and whenever the relative value is determined, a computation is done in a CPU at the data processing section 13 in terms of wavelength.