Optimized lens design for small angle uniform illumination from an extended source

Based on the edge-ray principle of non-imaging optics, an optical design method for a lens producing small angle, uniform illumination from a high-power light-emitting diode light source has been developed. The energy correspondence between the light-emitting diode light source and the illuminance distribution on a target plane was established, and a number of discrete points for freeform profile curves which could achieve uniform illumination over a small angle were calculated and fitted to create a lens. Finally, simulations were performed using software. The influence of the size of light source on the emitting angle under uniform illumination was also investigated. The results show that the optical system can achieve uniform illumination with an extended source, the divergence angle being controlled within a minimum range by the optical design method.