次波長週期性微結構被廣泛的應用在抗反射膜片，可大幅降低光學表面反射率，有效達到抗反射之目的。本研究利用有限時域差分法(FDTD)之演算，設計並分析模擬電磁波在各種複合式的次波長週期性微結構中傳遞的物理現象，模擬的波段設定在400nm – 800nm，約略為可見光的範圍。在此新的複合式微結構下，光波的反射率有明顯的下降，對照以往文獻中提到的單一圓柱陣列或金字塔型陣列之抗反射微結構，約改善39% - 57 %，並經由空間密度的概念分析反射率高低之成因，在各種不同結構中提供最佳比例以增加抗反射之效率。 Based on finite difference time domain method, an optical film surface with subwavelength periodic structure is numerically investigated to improve antireflection property. A improved subwavelength periodic structure is designed by finite difference time domain method, and it can be simulated effective. The antireflection properties of new types of subwavelength structures with different aspect ratios in spectral range of 400–800 nm are analyzed and compared. It is shown that, for the mixing type, the average reflectance is decreased and the variances of the reflectance are evidently smaller. When use the improved structure with a better aspect ratio, the average reflectance of the surface can be improved from 39% ~57%. Obviously, the antireflection properties of the optical film surface with new subwavelength structures can be improved.
