Fig. 1. Diagram of light distribution principle ofsingle free-form surface lens

Fig. 2. Secondary optical design of point source for uniform illumination. (a) Profile of light distribution lens; (b) diagram of uniform illumination principle

Fig. 3. Three-dimensional solid model of light distribution lens designed for point source

Fig. 4. Illuminance distributions of approximate point source. (a) Two-dimensional distribution; (b) one-dimensional distribution

Fig. 5. Illuminance distributions of extended source. (a) Two-dimensional distribution; (b) one-dimensional distribution

Fig. 6. Two-dimensional and one-dimensional illuminance distributions of approximate point source with different shifts in positive direction of y axis. (a) Shift of 1 mm; (b) shift of 2 mm; (c) shift of 3 mm

Fig. 7. Degradation reasons of illumination effect of extended source

Fig. 8. Principle of uniform illumination of extended source in refractive index pre-compensation method

Fig. 9. Profile of light distribution lens modified by refractive index pre-compensation method

Fig. 10. Illuminances of point source after modifying by refractive index pre-compensation method. (a) Two-dimensional distribution; (b) one-dimensional distribution

Fig. 11. Illuminances of extended source after modifying by refractive index pre-compensation method. (a) Two-dimensional distribution; (b) one-dimensional distribution