蓝光过滤多层功能薄膜的遗传算法设计

目的设计出一种在380~455 nm波段具有高反射率,但在500~760 nm波段具有低反射率的多层薄膜结构。方法采用遗传算法,采取截断选择策略,并引入小生境技术,选择灵活性较好的容差型评价函数,通过改变目标反射率,使功能薄膜在可见光波段具有增透与增反两种特性。采用八层不同折射率材料交替结构,计算得出满足光谱特性要求的全局膜系结构参数。结果当材料为硫化锌和氟化镁,厚度为324、142、68、46、51、51、56、145 nm时,380~455 nm波长处的平均反射率高达88.54%,500~760 nm波长处的平均反射率仅为2.00%。由几种常用光学薄膜材料的不同搭配,发现材料的折射率差与两波段的平均反射率差呈现相同趋势。当两种材料的折射率差为0.92时,两波段的平均反射率差为86.54%。结论采用的遗传算法可以简单有效地对多层薄膜结构进行优化,为获得较为理想的蓝光过滤功能薄膜,应尽可能选择折射率差大的两种材料。

Genetic Algorithm Design for Blue Light Filter Multilayer Functional Film

The work aims to design a multilayer film structure which exhibits high average reflectivity in 380 ～455 nm waveband,and low average reflectivity in 500～ 760 nm waveband.Genetic algorithm and truncation selection strategy were adopted to design the multilayer films structure by introducing ecological niche technology.Tolerance evaluation function of good flexibility was chosen to endow functional film with anti-reflection and enhancement reflection characteristics in visible light band by changing target reflectivity.Overall film structure parameters required to meet spectral characteristic requirements were obtained by using eight-layer structure of altemate refractive index materials.When the materials were zinc sulfide and magnesium fluoride,and were 324,142,68,46,51,51,56 and 145 nm thick,respectively,average reflectivity of the film was up to 88.54％ in 380～ 455 nm waveband,and only 2.75％ in 500 ～ 760 nm waveband.According to different collocation of several common optical film materials,refractive index difference of refractive index materials shared the same trend with average refractive index difference between two wavelengths band.The difference of average reflectivity between two wavebandswas 86.54％.When the refractive index difference between two materials was 0.92,average refractive index difference in two wavebands was 86.54％.The algorithm can effectively optimize the multilayer film structure.Two materials differing a lot in refractive index shall be selected as far as possible to obtain ideal blue light filter functional film.