An innovative design of light collimator based on freeform microlens array

This study presents an innovative freeform lens used in the NLIS (Natural Light Illumination System). The NLIS is used to guide the natural light indoors for illumination, which system is implemented in energy saving smart buildings to reduce energy consumption. The freeform lens is based on microlens array to collimate the light from the collecting sub-system before entering the light transmitting sub-system. Results show better parallelism can be achieved for later light transmission.