Angular uniformity of cascaded integrating sphere radiation source

In order to design and manufacture integrating sphere radiation sources with high angular uniformity, it is necessary to provide optimized design parameters. Based on the radiative transfer theory of cavity, a simulation model of light exitance distribution of light-emitting unit based on cascaded integrating sphere structure was established, and the relationship between the installation position of the Lambertian light-emitting unit and the angular uniformity of the cascaded integrating sphere radiation source was obtained. The simulation results showed that, in ideal conditions, when two Lambertian cascaded sub-spheres were used as light-emitting units and were symmetrically installed at an angle of 10° with the normal direction of the light outlet of the cascaded integrating sphere radiation source, the angular uniformity in the observation area at an angle of ±20° between the center of the sphere and the normal direction of the light outlet could reach the level of 0.03%. Finally, the angular uniformity of the cascaded integrating sphere radiation source at the 30° angle position of the cascaded sub-spheres was measured experimentally, and the experimental results were close to the simulation results. Therefore, by optimizing the type and installation position of the light-emitting unit, the angular uniformity of the integrating sphere radiation source could be effectively improved.