傳統光譜儀多以羅倫圓結構製作，但羅倫圓結構有個缺點，即聚焦位置僅能在弧面上，市面上的偵測器多為平面的，故以平面偵測器做接受器時，像差會增大，本文的光柵結構結合具有光柵的分光能力及凹面鏡具聚焦功能的優點，並盡量使聚焦點聚在一平面上。本文一開始會先介紹有關光柵的相關理論，並以光程函數推導出像差公式，本文將此為基礎，找出合適的參數來建立模型，並以光學軟體驗證之，本文成功的制作出可使聚焦點聚在一平面的類周期性結構。

The shortcoming of Rowland circle is the focus plane only could focus on cambered surface, but most of the detectors in the market focus on plane surface.
If we use the plane detector for receptor, the aberration will increase.
In this article, the structure of grating has two advantages, one is capability for grating spectr, and another is function for focusing on concave mirror, and made the focus point focused on one plane as much as possible.
In the beginning of article has introduced the related theory of grating, and used the optical path function to derive aberration equation.
This article is base on the above, and find out the applicable parameter to build model. We also use the optical software to verify, and make the grating successful which the focus point could focus on one plane.

[1] 王以撒，“光波導多工器中凹面梯形光柵之研究”，光電科學研究所碩士論文，2002。
[2] 張建中，“凹面型光柵光譜儀應用於水果糖度檢測之研製”，國立屏東科技大學機械工程系碩士論文，2003
[3] 張世易，“霍氏轉換紅外光譜儀在氣態化合物量測上的發展與應用”， 國立清華大學生醫工程與環境科學系博士論文，1996
[4] 江英澤，“ 非球面閃耀式微光柵設計與光罩製作”， 國立中央大學機械工程研究所碩士論文，2004
[5] Born, M., E. Wolf, “Principles of Optics,” Pergamon, Oxford, 1980.
[6] Lijun Lu, “ Optimization of constant-length Rowland-Circle
monochromator with a varied line-spacing grating”, CHINESE OPTICS
LETTERS,Vol. 2,No. 11,November 10,2004
[7] S. Singh, “Diffraction gratings: aberrations and applications”, Optics and Laser Technology, 31, 195-218, 1999.