近年來，能源耗竭，綠色產業越來越被重視，各國產業與學者為了節約能源及健康照明，設計了將太陽導進室內做照明的技術，稱為自然光照明系統。然而，自然光照明系統會因為太陽光在不同時間的能量不同，而不穩定。為了提供高穩定的室內照明，必須使用LED做補光。本論文中提出了一個自由曲面透鏡，可以結合LED及自然光照明系統。這自由曲面透鏡可以使得兩種不同配光曲線的光源變成相同的配光曲線，而可以同時使用自然光照明系統及LED做照明。通過這樣的設計，可以使得太陽光在不同的時間下都可以達到均勻度為84.00%且效率為81.32%的室內照明。

In response to the energy shortages, the green energy has been gaining popularity in recent years. For saving energy and healthy lighting, many researches focus on designing a system that is able to gather sunlight for indoor lighting, ex: HIMAWARI, SOLUX…etc. However, these systems are not stable because the sunlight has different energy at different moment. In order to provide stable indoor illumination, LED must be applied to compensate for the lack of power. In this paper, we present a novel freeform lens, which can combine the nature light illumination systems and LED. This freeform lens can let two different luminous intensity distribution sources become the same output distribution. Therefore, we could use the nature light illumination systems and LED for illumination at same time. Through this design, we can steadily provide indoor illumination of 84.00% uniformity and 83.82% efficiency.

[1] 綠色能源發展趨勢
http://www.yfes.tn.edu.tw/environment/main4.files/4-1.htm
[2] 黃瑋，應用於室內照明之自然導光拋物體集光器設計，碩士論文，國立台灣科技大學電子工程系碩士論文，台北(2008)
[3] Whang AJW, Chen YY, Wu BY. Innovative design of Cassegrain solar concentrator system for indoor illumination utilizing chromatic aberration to filter out ultraviolet and infrared in sunlight. Solar Energy 2009; 83:1115–1122.
[4] Whang AJW, Wang CC, Chen YY. Design of cascadable optical unit to compress light for light transmission used for indoor illumination. Renewable Energy 2009; 34: 2280–2295.
[5] Callow J. Daylighting using tubular light guide systems. PhD thesis. Nottingham: University of Nottingham, 2003.
[6] Whang AJW, Chen YY, Yang SH, Pan PH, Chou KH, Lee YC, Lee ZY, Chen CA, Chen CN. Natural light illumination system. APPLIED OPTICS 2010; 49:6789-6801.
[7] Y.K. Cheng and J.L. Chern. Irradiance formations in hollow straight light pipes with square and circular shapes. J. Opt. Soc. Am. A 2006;23: 427-34.
[8] G.B. Smith. Materials and systems for efficient lighting and delivery of daylight. Solar Energy Materials & Solar Cells 2004;84: 395-409.
[9] 李碩重，「照明設計學」，全華圖書股份有限公司，民國九十六年九月。
[10] CNS 照度標準，標準總號12112，類號Z1044，民國七十六年九月十七日。
[11] 張智鴻，人工智慧應用於室內照明最佳化設計之研究，國立台灣科技大學，碩士論文，台北(2006)。
[12] Jin-Jia Chen, T.-Y.W., Kuang-Lung Huang, Te-Shu Liu, Ming-Da Tsai, and Chin-Tang Lin, Freeform lens design for LED collimating illumination 2012 Optical Society of America, 7 May 2012.
[13] Lin Wang, K.Q., and Yi Luo, Discontinuous free-form lens design for prescribed irradiance. 2007 Optical Society of America, 15 February 2007.
[14] Mikhail A. Moiseev, L.L.D., and Nikolay L. Kazanskiy Design of high-efficient freeform LED lens for illumination of elongated rectangular regions 2011 Optical Society of America, 10 Mar 2011.
[15] Yi Ding, X.L., Zhen-rong Zheng, and Pei-fu Gu, Freeform LED lens for uniform illumination. 2007 Optical Society of America, 18 August 2008 / Vol. 16, No. 17.
[16] Yi Luo, Z.F., Yanjun Han, Hongtao Li, Design of compact and smooth free-form optical system with uniform illuminance for LED source. 2010 Optical Society of America, 6 Apr 2010.
[17] 謝瑋哲，非聚焦式自由曲面透鏡圓盤集光器，國立台灣科技大學，碩士論文，台北(2011)。
[18] 陳偉安，具光學結構設計之高效率傳光管，國立台灣科技大學，碩士論文，台北(2012)
[19] 呂明君，以LED矮路燈設計為例之非軸對稱式自由曲面設計，國立台灣科技大學，碩士論文，台北(2011)。
[20] 馬啟唐，交錯式雙層透鏡陣列應用於自然光照明系統之靜態式集光器，國立台灣科技大學，碩士論文，台北(2011)。