近年來全球暖化的議題已成為人類發展的重大問題。減少化石燃料耗損和節約能源為目前首要的任務。再生能源廣泛被應用，其中，太陽能源為地球上最重要且豐富的資源之一。若將太陽能源直接導引至室內，有效提供建築用電或室內照明所需，不只可以節約能源，更可以提供舒適且健康的照明環境。因此我們研究團隊發展了自然光照明系統，為了於室內發展高品質的日照光源，提高系統效率為首要的目的。於自然光照明系統中利用集光器收集陽光，並藉由導光管或光纖導引至室內，然而隨著集光器的集光面積增加，集光效率明顯下降。
為了維持高效率傳輸，我們將集光器模組化，並設計新式耦合元件，耦合器的結構包含聚光和導光的雙通道設計，根據集光器的配光曲線進行多段式曲率設計，相似於球面設計概念，透過聚焦原理將光線進行壓縮，便於光線進行高能量傳輸。再透過導光層的概念，將四片集光器所收集到的所有光線統一集中成單一出口出光，減少75% 導光管和光纖的使用量，同時增加整體的傳輸效率。在相同集光面積下，集光器透過耦合器的串接，提高了23.29 ％的整體集光效率，為原本未加耦合器的2.68倍。模組化設計的概念降低傳光元件得使用量，同時減少成本和擺放面積，使自然光照明系統可以更有效運用於建築物或任何想安裝的地方。

Nowadays, global warming has become a major issue. Reducing the consumption of fossil fuel and saving energy were the top priorities. In response to the energy crisis, renewable energy has been widely taken as other energy options. Solar energy is one of the most essential and abundant energy. If we can collect and transmit natural light into buildings without opto-electronic conversion, that will save energy and provide healthier light into our daily life. Therefore, our team designed a series of products known as Natural Light Illumination System (NLIS). In developing the high-quality NLIS, our primary concern was to increase the efficiency of the system. When the concentrators in daylight system collects sunlight, the light transmits through light pipe or fiber to any room you want. However, the efficiency decreases dramatically as the number of concentrator increases, due to the interconnection parts which encounter huge loss.
For high-efficiency light transmission, the paper presents a design of coupler which assembles concentrators in module. The coupler consists of two structures, convergent element and light guide. According to the candle power distribution curve of the concentrator, we created the convergent element with multi-stage curvature. The concept of the multi-stage curvature is similar to the spherical surface which can compress sunlight smaller. Furthermore, the light guide gathered all light from concentrators and guided to the single exit port, which reduced the number of transmitting component. The module with coupler improved 23.29 % in efficiency with the same collecting area, which was 2.68 times higher. Furthermore, the lower transmitting components were not only lower cost and area but also easy to set up in the building or any place you want.

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