1986 Volume 70 Issue 10 Pages 545-549
The absolute spectral reflectance in 0/d condition (ρ (λ)) of Several white diffusers have been measured by third Taylor's method, using the integrating sphere of usual spectrophotometer and the relative spectral radiance factor in 0/45° condition (B45 (λ)) of same samples are also measured by simple goniometric method. The wavelength region of measurements are 210-2, 500 nm in ρ (λ), and 280-760 nm in B45 (λ). The samples of these measurements are the pressed BaSO4, LiF, flowers of sulfur and the sintered Al2O3 plate. The results of ρ (λ) and B45 (λ) are compared respectively for same sample. The reflectance change with the passage of time is also measured for some samples. The results are as follows;
(1) ρ (λ) on the pressed BaSO4 is over 90% in the wavelength region of 320-1, 800 nm, but that goes down in the regionshorter 300 nm and that has remarkable dips in the region longer than 1, 800 nm.
(2) ρ (λ) on the pressed LiF is same as that on BaSO4 in visible (VIS) region and is somewhat higher than that on BaSO4 in ultraviolet (UV) and infrared (IR) region.
(3) ρ (λ) on the sintered Al2O3 is same as that on BaSO4 in VIS region and is higher than that on BaSO4 in IR region, but goes down suddenly in UV region.
(4) ρ (λ) on the pressed flowers of sulfur is almost constant in the wavelength region of 700-2, 200 nm, but goes down in the wavelength region shorter than 600 nm.
(5) On the pressed BaSO4 and LiF, the relative value of ρ (λ) is consistent with the B45 (λ) in the wavelength region of 320-760 nm.
(6) On the pressed BaSO4 and LiF, the difference of ρ (λ) on samples which are made from same lot and the change of ρ (λ) with the passage of time are very small through the measurement period (about half a year).