EVALUATION OF THE INFLUENCE OF AN INTEGRATING SPHERE INTERNAL STRUCTURE ON TOTAL LUMINOUS FLUX MEASUREMENT

We examined the uniformity of the spatial response distribution function (SRDF) within an integrating sphere in which a baffle with a complex shape had been installed. The SRDF was measured by illuminating an inner surface of an integrating sphere with a spot light and also calculated by numerical simulation. Based on these SRDF results, we established a guiding principle for estimating the uncertainty of the total luminous flux measurement based on the difference in the light distribution between a test light source and a standard light source. Although differences of up to 0,4 % were observed between the total luminous flux obtained in the numerical simulation and that obtained in the experiment, the basic overall tendency of the light distribution dependence was reproduced well in the simulation. This result suggests that it may be possible to apply numerical simulations to determine optimum baffle shapes.