Fig. 1. Irradiance distribution generated by cascaded sub-sphere in integrating sphere

Fig. 2. Simulation model of integrating sphere radiation source with randomly distributed light-emitting units

Fig. 3. Relative reflected radiance distribution curves of symmetrically distributed cascaded sub-sphere at position γ in area ±α

Fig. 4. Relative standard deviation of reflected radiance value in area ±α when angle γ taking points at equal intervals of 20°

Fig. 5. Relative standard deviation of reflected radiance distribution of angle distribution of γ₁, γ₂ and in area ±α

Fig. 6. Optimal solution of relative standard deviation and corresponding angular distribution of γ₁, γ₂

Fig. 7. Schematic block diagram of experimental device

Fig. 8. Structure diagram of cascaded integrating sphere

Fig. 9. Test data curve of light source stability

Fig. 10. Test data curves of horizontal angular uniformity

Fig. 11. Test data curves of vertical angular uniformity