Sunlight is the most environmental-friendly energy. Through the Natural Light Illumination Systems (NLIS® ),
we can guide sunlight indoors to use. However, due to the construction cost of the NLIS® , the most cost is spent on the optical fiber. Therefore we intend to design an element that can re-shape the beam from the SunLegoreg; to be narrower, where SunLego® is the building unit of NLIS® for light collection. The element consists of two functional optical structures: the first structure is to convert light from SunLego® to parallel beam, technically, is to convert stray light to parallel. We design the first structure based on free form principle. The second is a fan-shaped structure, which is to reduce the light transmission area , this design is based on the E'tendue principle. The reduction of area means we can use smaller fiber for later light transmission, which is crucial to reduce material cost.