Due to the energy crisis, the principle of green energy gains popularity. This leads the increasing interest in
renewable energy such as solar energy. Thus, how to collect the sunlight for indoor illumination becomes our ultimate
target. With the environmental awareness increasing, we use the nature light as the light source. Then we start to
devote the development of solar collecting system. The Natural Light Guiding System includes three parts, collecting,
transmitting and lighting part. The idea of our solar collecting system design is a concept for combining
the buildings with a combination of collecting modules. Therefore, we can use it anyplace where the sunlight can directly
impinges on buildings with collecting elements. In the meantime, while collecting the sunlight with high efficiency, we
can transmit the sunlight into indoor through shorter distance zone by light pipe where we needs the light.
We proposed a novel design including disk-type collective lens module. With the design, we can let the incident
light and exit light be parallel and compressed. By the parallel and compressed design, we make every output light
become compressed in the proposed optical structure. In this way, we can increase the ratio about light compression, get
the better efficiency and let the energy distribution more uniform for indoor illumination. By the definition of "KPI" as
an performance index about light density as following: lm/(mm)2, the simulation results show that the proposed
Concentrator is 40,000,000 KPI much better than the 800,000 KPI measured from the traditional ones.