Fig. 1. The influence caused by the tilt of freeform reflector

Fig. 2. Two-dimensional coordinate system of a freeform reflector

Fig. 3. Design principle of freefrom reflector

Fig. 4. Coordinate system of tilted illumination

Fig. 5. Design flow chart of freeform reflector

Fig. 6. Schematic diagram of Chebyshev points sampling

Fig. 7. Schematic diagram of simulated freeform reflector

Fig. 8. Schematic diagram of the optical path

Fig. 9. Schematic diagram of irradiance on the target plane

Fig. 10. Schematic diagram of the square illumination area

Fig. 11. Schematic diagram of irradiance before optimization

Fig. 12. Schematic diagram of irradiance after optimization