Research on the influence of baffle in luminous flux measurement with integrating sphere

In the field of optical metrology, luminous flux is an important index to characterize the quality of light source. There are two kinds of method to measure it that one is light distribution surface method and the other is integrating sphere method. In the integrating sphere method, the baffle which is a key part of integrating sphere has important effects on the measurement results. The paper analyzes in detail the principle of an ideal integrating sphere. We change the relative position and shape of baffle inside the sphere during testing. By experiments, measured luminous flux values at different distances between the light source and baffle are obtained, which we used to take analysis of the effects of different baffle position and shape on the measurement. And then we obtain the optimum position and shape of baffle for luminous flux measurements. Based on the conclusion, we develop the methods and apparatus to improve the luminous flux measurement accuracy and reliability, which makes our unifying and transferring work of the luminous flux more accurate in East China and provides effective protection for our traceability system