Comparison of Total Luminous Flux for Integrating Sphere Photometers

A mutual comparison of the measured values of the total-luminous-flux between the sphere photometers when using an integrating sphere in which the sizes differ was made, and the consistency was also considered. The same total-luminous-flux standard lamp was used to prevent affecting measured value to standard traceability. The LED lamps used for measurement were turned on for 100 hours or more. The reproducibility for all the lamps was less than ±0.2%. The total-luminous-flux of omnidirectional lamps with an angular luminous intensity distribution was the same as that for a standard lamp, which is accorded in less than 1% in the spheres. On the other hand, the total-luminous-flux of directional lamps was accorded in more than 1.5% in spheres. The low light flux value measured by using the integrating sphere with a 1- m o diameter is considered to be the influence of the lamp support stand and another structure in the integrating sphere. Since the measured value of the integration hemisphere is the same as that of the large integrating spheres, there is very little structure that is causing the error with it.