Fig. 1. Light intensity distribution of point source

Fig. 2. Principle of light intensity mapping method

Fig. 3. Principle of HPE method

Fig. 4. Schematic diagram of inner freeform surface

Fig. 5. Schematic diagram of ideal refracted ray after incident ray passes through inner freeform surface

Fig. 6. Schematic diagram of outer freeform surface

Fig. 7. Point source approximate design results. (a) Two-dimensional outline; (b) three-dimensional outline; (c) illuminance distribution spot

Fig. 8. Outline of the lens. (a) Two-dimensional outline; (b) three-dimensional outline

Fig. 9. Simulation results. (a) Optical path diagram; (b) illuminance distribution light spot; (c) illuminance distribution curve

Fig. 10. Optimized results. (a) Optimized 3D profile of the lens; (b) illuminance distribution spot; (c) illuminance distribution curve

Fig. 11. Simulation results under various lighting distances. (a) 2 m; (b) 10 m; (c) 50 mm; (d) 100 mm

Fig. 12. Simulation results when the ratio of distance to height is 1.5. (a) 3D profile of the lens; (b) illuminance distribution spot

Fig. 13. Simulation results of rectangular source

Fig. 14. Simulation results of near field and far field illumination of point light source. (a) 100 mm; (b) 1000 mm